It depends on where you live if the vet can dock the dog's tail or not.
If the dog is in pain most will allow this as a medical procedure but your vet has to agree there is a problem.
You can ask if your vet can remove the tail and be sure to tell them that the dog is snapping if the tail is touched and could be a danger to people or children.
Hope this helps you!
Dog Expert:Rescue, Train,Breed,Care
30+ yrs dog home vet care & nursing, rescue, behavior&training, responsible show breeding, genetics