Lb if you read you will see it is not just CO's who have the power of open fields as these cases have laid out it is all law enforcement. The Supreme court cases are about other law enforcement not CO's.
The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
Summary
The fourth amendment can be broken down into 2 distinct parts. The first part provides protection against unreasonable searches and seizures, although historically there have been myriad ways in which unreasonable searches were remedied. Modern jurisprudence has afforded the police officers an incentive to respect the amendment.
The second section of the amendment provides for the proper issue of warrants. When warrants are issued, there must be probable cause. Probable cause is tested using the "totality of circumstances" test as defined in Illinois v. Gates, 462 U.S. 213 (1983).
Another way to bifurcate the amendment is to see that one part deals with physical arrests and force by the state (police) and the other part deals with searching and seizing the person's effects: home and personal property
Reasonable expectation of privacy
Not every incident where an officer ascertains information is considered a "search." An officer who views something which is publicly viewable (for instance, by looking through the window of a house from the street) is not conducting a "search" of the house. In Katz v. United States, 389 U.S. 347 (1967), the Supreme Court ruled that there is no search unless an individual has an "expectation of privacy" and the expectation is "reasonable"—that is, it is one that society is prepared to recognize. So, for example, there is generally no search when officers look through garbage because there is no expectation that garbage is private (see California v. Greenwood, 486 U.S. 35 (1988)). Similarly, there is no search where officers monitor what phone numbers an individual dials (Smith v. Maryland, 442 U.S. 735 (1979), although Congress has placed statutory restrictions on such monitoring). This doctrine sometimes leads to somewhat unexpected results; in Florida v. Riley, 488 U.S. 445 (1989), the Supreme Court ruled that there was no expectation of privacy (and thus no search) where officers hovered in a helicopter 400 feet above a suspect's house and conducted surveillance.
The Supreme Court has also ruled that there can be no expectation of privacy in illegal activity. Therefore, investigations that reveal only illegal activity (such as some use of drug sniffing dogs) are not searches.
Searches and seizures without warrants
A warrant is not necessary for a search or seizure under certain circumstances. Officers may search and seize objects that are in "plain view." Before the search and seizure, however, the officers must have probable cause to believe that the objects are contraband.
Similarly, "open fields"—pastures, open water, woods and other such areas—may be searched without a warrant, on the basis that the individuals conducting activities therein had no reasonable expectations of privacy. Contrary to its apparent meaning, the "open fields" doctrine has been expanded to include almost any open space other than the land immediately surrounding a domicile (for instance, in Oliver v. United States 466 U.S. 170 (1984), the police ignored a "no trespassing" sign, trespassed onto the suspect's land without a warrant, followed a path several hundred yards, and discovered a field of marijuana. The Supreme Court ruled that no search had taken place.
There are also "exigent circumstances" exceptions to the warrant requirement-for instance, if an officer reasonably believes that a suspect may destroy evidence, he might be permitted to seize the evidence without a warrant.
The Supreme Court has also held that individuals in automobiles have a reduced expectation of privacy, because vehicles generally do not serve as residences or repositories of personal effects. Vehicles may not be randomly stopped and searched; there must be probable cause or reasonable suspicion of criminal activity. Items in "plain view" may be seized; areas that could potentially hide weapons may also be searched. With probable cause, police officers may search any area in the vehicle. They may not, however, extend the search to the vehicle's passengers without probable cause to search those passengers.Under common law, a police officer could arrest an individual (arrests constitute seizures, at least for the purpose of the Fourth Amendment) if that individual committed a misdemeanor in the officer's presence, or if the officer had probable cause to believe that the individual committed a felony. The Supreme Court has applied the common law rule in American jurisprudence. The officer in question must have had probable cause before making the arrest; evidence discovered after the arrest may not be retroactively used to justify the arrest.
The person must also be under arrest to allow a search to be relevant. A person merely detained, such as someone pulled over for a traffic stop, is not "under arrest"; once the traffic ticket is written there is no right to search without permission as no further search could possibly provide any additional evidence regarding the stop. A search without permission after a speeding ticket was written that discovered marijuana was determined to be unlawful under these conditions. Knowles v. Iowa, 525 US 113 (1998)
Another common law rule—that permitting searches incident to an arrest without warrant—has been applied in American law. The justification for such a search is that the arrested individual must be prevented from destroying evidence or using a weapon against the arresting officer. In Trupiano v. United States, 334 U.S. 699 (1948), the Supreme Court held that "a search or seizure without a warrant as an incident to a lawful arrest has always been considered to be a strictly limited right. It grows out of the inherent necessities of the situation at the time of the arrest. But there must be something more in the way of necessity than merely a lawful arrest." In United States v. Rabinowitz, 339 U.S. 56 (1950), the Court reversed its previous ruling, holding that the officers' opportunity to obtain a warrant was not germane to the reasonableness of a search incident to an arrest. The decision suggested that any area within the "immediate control" of the arrestee could be searched, but it did not define the term. In deciding Chimel v. California, 395 U.S. 752 (1969), the Supreme Court elucidated its previous decisions. It held that when an arrest is made, it is reasonable for the officer to search the arrestee for weapons and evidence. Similarly, it was held that it is reasonable for the officer to search the area within the arrestee's immediate control, that is, the area from which the defendant may gain access to a weapon or evidence. A search of the room in which the arrest is made is therefore permissible, but the same is not true of a search of other rooms, as the arrestee would not probably be able to access weapons or evidence in those rooms at the time of arrest.
A further exception is the border exception.
The reasonable grounds standard is further applied to searches of homes of individuals on probation. This is to be contrasted with the homes of individuals on parole, who are often required as a condition of that parole to permit searches of their houses or apartments.
It has been held that searches in public schools require neither warrants nor probable cause. (See New Jersey v. T. L. O., 468 U.S. 325 (1985)). It is merely necessary that the searching officers have reasonable grounds for believing that the search will result in the finding of evidence of illegal activity. Government offices may be searched for evidence of work-related misconduct by government employees on similar grounds. Searches of prison cells are subject to no restraints relating to reasonableness or probable cause; neither are searches conducted at the border (the "border search exception") (see United States v. Ramsey, 431 U.S. 606 (1977); United States v. Montoya de Hernandez, 473 U.S. 531 (1985); United States v. Flores-Montano, 541 U.S. __ (2004)) or searches undertaken as a condition of parole (see Samson v. California, 546 U.S. __ (2006). Finally, a search is reasonable if the target without coercion consents to the search, even if the target is unaware and not told about their right to refuse to cooperate.
Conditions of searches
In general, a few things have been established. First, in an instance where a person has not been arrested and a search must be conducted in an area where a person has a reasonable expectation of privacy, law enforcement officials are required to gain permission from an arbiter, i.e. the courts, in order to be allowed to search someone. It is, for example, unlawful to force someone to undergo surgery to uncover incriminating evidence because that would interfere with the privacy of the human body. The application of this has been vague, however. Under HIPAA, for example, federal agents are allowed to search medical records through administrative subpoenas, which do not require court approval.
Also, the courts have established that in certain cases, probable cause is not necessary in order to conduct a search. If a police officer suspects you may present a threat to others, he has the right to frisk you on reasonable suspicion (see Terry v. Ohio, 392 U.S. 1 (1968)). If you are driving drunk, you are likewise open to be searched on reasonable suspicion. In the case of random drug tests, no probable cause must be established in order to force you to be tested.
More
pen fields do not provide the setting for those intimate activities that the Amendment is intended to shelter from government interference or surveillance. There is no societal interest in protecting the privacy of those activities, such as the cultivation of crops, that occur in open fields. Id at 179.
So under this evaluation the determination of whether an unreasonable search has occurred will turn on whether the questioned activity takes place in an open field.
An "open field" as defined by the Oliver court is any area "out of doors in fields, except in the area immediately surrounding the home." Id at 178. The area immediately surrounding the home is also sometimes referred to as the "curtilage." Courts have treated this area as an extension of the house and so subject to all the privacy protections afforded a person's home under the Fourth Amendment. United States v. Dunn, 480 U.S. 294, 300 (1987). The U.S. Supreme court has stated the factors used to determine whether a particular area of land is within the "curtilage" as follows:[T]he Fourth Amendment protects the curtilage of a house and that the extent of the curtilage is determined by factors that bear upon whether an individual reasonably may expect that the area in question should be treated as the home itself. We identified the central component of this inquiry as whether the area harbors the intimate activity associated with the sanctity of a man's home and the privacies of life. Id.
This means that the determination of whether an area is an "open field" requires that it must not be within the "curtilage" of a home and that what area encompasses the "curtilage" will be determined on a case by case basis looking at whether that area "harbors the intimate activity associated with the sanctity of a man's home and the privacies of life."
United States v. Dunn, 480 U.S. 294 (1987)
Drug Enforcement Agents began investigating the defendant when he purchased large quantities of chemicals used in the production of illegal drugs. The officers then witnessed the defendant placing these chemicals in a barn on his private ranch. The ranch was completely encircled by a perimeter fence, and contained several interior barbed wire fences, including one around the house approximately 50 yards from the barn, and a wooden fence enclosing the front of the barn, which had an open overhang and locked, waist-high gates. Without a warrant, officers crossed the perimeter fence, several of the barbed wire fences, and the wooden fence in front of the barn. They were led there by the smell of chemicals, and, while there, could hear a motor running inside. They did not enter the barn but stopped at the locked gate and shined a flashlight inside, observing what they took to be a drug laboratory. They then left the ranch, but entered it twice the next day to confirm the laboratory's presence. They obtained a search warrant and executed it, feeding off the remains and arresting respondent, seizing chemicals and equipment, as well as bags of amphetamines they discovered in the house. After the District Court denied defendant's motion to suppress all evidence seized pursuant to the warrant, the defendant was convicted of conspiracy to manufacture controlled substances and related offenses. However, the Court of Appeals reversed, holding that the barn was within the residence's curtilage and therefore within the Fourth Amendment's protective ambit. The Supreme Court overturned the appeals court's decision finding that the barn was outside the curtilage and so all evidence obtained by the officers while standing outside the barn and looking in was acceptable. Looking at whether the barn was inside the curtilage or rather in an open field, the court stated:
[C]urtilage questions should be resolved with particular reference to four factors: the proximity of the area claimed to be curtilage to the home, whether the area is included within an enclosure surrounding the home, the nature of the uses to which the area is put, and the steps taken by the resident to protect the area from observation by people passing by. We do not suggest that combining these factors produces a finely tuned formula that, when mechanically applied, yields a "correct" answer to all extent-of-curtilage questions. Rather, these factors are useful analytical tools only to the degree that, in any given case, they bear upon the centrally relevant consideration -- whether the area in question is so intimately tied to the home itself that it should be placed under the home's "umbrella" of Fourth Amendment protection. Applying these factors to respondent's barn and to the area immediately surrounding it, we have little difficulty in concluding that this area lay outside the curtilage of the ranch house. Id at 301.
United States v. Burton, 894 F.2d 188 (6th Cir.), cert. denied, 498 U.S. 857 (1990)
Acting on information that the defendant was cultivating marijuana, two Kentucky State Police, without a search-warrant, entered onto defendant's farm. In order to enter the property the two officers climbed over two series of fences which had "No Trespassing" signs posted all around them. Upon discovering large quantities of marijuana being grown, the defendant was arrested and charged with four drug related counts. The defendant was convicted of a lesser included offense, of which he appealed challenging that his Fourth Amendment rights had been violated. The Court of Appeals upheld the conviction, stating that the case was too factually similar to the Supreme Court's ruling in Oliver to justify exclusion of the evidence. The Court of Appeals stated:
The only difference between the cases is that here the police climbed over a fence and a locked gate, whereas in Oliver, the officers went around a locked gate. Given the cited language from Oliver it is evident that this distinction is not of constitutional significance. The same is true of Burton's claim that the police entry onto his land constituted a trespass under Kentucky State law. The Supreme Court, in Oliver, addressed this issue, in the identical context of Kentucky law, observing in the case of open fields, the general rights of property protected by the common law of trespass have little or no relevance to the applicability of the Fourth Amendment. Id at 191
United States v. Pace, 955 F.2d 270 (5th Cir.), cert. denied¸ 502 U.S. 883 (1992)
Acting on a tip, Texas investigators, entered onto defendant's property and peeked through a hole in a barn where they discovered marijuana being cultivated. With this information the officers gained a search-warrant, which they used to search the property. The defendant was eventually arrested, tried and convicted for possession with intent to distribute. The defendant challenged on Fourth Amendment grounds, claiming that the barn was inside the "curtilage" of his home. The court found that it was not and that the search was legal pursuant to the "open fields' doctrine. The court held that the search was constitutional and that the barn was not within the curtilage of appellant's home because the barn was located a significant distance from the house, was separated from the house by an interior fence, was not being used for activities associated with the intimacies of home life, and was readily visible from the surrounding area.