There's two different kind of cribbin, the first is suckin air and swollowin it, sometimes they bite onto somethin and stretch their neck out then swollow, sometimes not.  Improper diet and feedin has also been found  to contribute to cribbin.

Cribbin can lead to serious health problems, such as poor digestion, colic, and all sorts of dental problems.

The other more common type of cribbin is chewin stall or fence boards. Horses that are pastured are less likely than one's kept in a stall. It's not known what causes them to do this for sure, but boredom and stress are thought to contribute to it. Horses in the wild have never been reported to crib (either form) because 90 percent of the time they are out grazin.

If it were me, it would depend on the amount of pasture I had to put this horse in, or if it would be kept in a stall. If I had no choice and it was to be in a stall, I'd not want one that was a cribber, no matter how good the horse. I've seen barns/stalls that are literally almost chewed up to the point of rebuilding, and it don't take em long for them to do it if they are bad about it.