As a former firefighter and County fire warden, I have had many a run in with federal firefighters (BLM, Fish and Wildlife) - and on many occasions had to do like you said and just pay them no heed up until the point that they assumed control of the fire- and we've had many heated go arounds with the powers to be after a fire.....
But I did have an experience that awakened me to one of the reasons they do not like unorganized volunteers on a fire- and why once they assumed control we either followed their orders or got out...
I was one of a 3 man crew that was running a pumper truck on a Missouri Breaks fire about 20 years ago...Our fire Dept. did not have the same radio frequencies as the feds and state lands firefighters had...We had done the initial attack on the fire and then stayed to help when the BlM brought in "yellowshirt" crews and took over control of the fire...
Come daylight the BLM fire boss called for a tanker drop on the west side where the fire was flaring up- he notified all his people by radio of the drop and to leave the west side area, and accounted for all of them- he was unable to contact us because of no radios, but assumed we were still on the east side of the fire where we had been fighting all during the night, not knowing that we had worked over to the west side about daylight and were vigorously trying to stop the flaring hotspot...
Luckily we had just ran out of water- were standing beside the truck taking a breather and saw the plane as it started its drop...We dove under the truck, which took full impact from the plane which I'm sure never saw us because of the smoke....The power of that slurry drop broke the windows out of the truck, tore the toplightbar off and even smashed us around under the truck...If we'd been caught in the open we would have been dead....
When the fire boss is put in charge of a fire he assumes responsibility and liability of everyone on that fire- and if you have unorganized persons that you cannot communicate to or have organized control over it complicates the situation...
Years of fighting fire brought me to the conclusion that rancher/farmer/civilian firefighters can be the greatest asset you have on a fire if you can utilize them correctly/ but can also be the biggest pain in the ash if they take off playing cowboy fireman on their own- and in most cases the Federal firebosses don't know how to utilize them.....