My gelding is a cribber and I've always used the V collar for the past 4 yrs and he has never cribbed with it on, it helps if they're pasture horses. And my horse is fed half a scoop of sweet feed twice a day and still no cribbing and he's a bad cribber, he'll even try to crib on the cross ties if the collar is off. So it should help, it's not the end of the world. I knew my horse was a cribber when i bought him and i wouldnt trade him for any horse in the world. There was a really good famous rider, for the life of me cant remember his name, that looked for cribbers. bc most of them seem to have a really good work ethic and drive but that's just my opinion.
"The horse you get off is not the same as the horse you got on; it is your job as a rider to ensure that as often as possible the change is for the better."