Ok...the dog growls at someone and just because its 4 months old you expect the vet to put her body at risk? Sure...find another vet if you want, but I wouldn't take a chance with a growling dog either. The dog probably can't do that much damage...but any damage to the vet's hand probably puts her at risk for not being able to do her job. Who knows...maybe its a tiny scratch, maybe its a little blood, or maybe the tooth nicks a nerve of some sort and the vet can't move her thumb for a week?
There is a world of difference between YOUR dog growling while playing with YOU. And YOUR dog growling at ANOTHER person. At my club...no dog is allowed to growl, no matter what age. My dog can growl while I'm playing tug with him, but if he even lets out a little one towards another dog or human, he will get corrected.
This vet is incompetent? Seriously?!?!? Because she wants to muzzle a GSD? You realize that vet probably sees a bunch of unruly, untrained, aggressive dogs on a daily basis. If putting a muzzle on is what the vet needs to do her job...let her do it. It doesn't hurt a dog any to have a muzzle on.
I love people making judgement about a vet and a puppy's intentions over a 4 paragraph post.
CD RE TC HIC 7/10