Would they be training him in front of you or would you be sending him away?
I'd never allow them to take my dog away from me if he were being trained as a family pet. You never know what methods they are using to get him to comply.
My breeder told me one of the owners that a friend of hers sold a puppy to came back complaining that the dog was viscous. It turned out he sent the puppy away for training, then when they were outside he picked up a stick and was about to throw it, instead of getting ready to chase the stick like a regular dog would, anyone that has ever been out on a field before can probably guess what the dog did
If you intend to have a "house dog", it would be in your best interest to be involved in your puppy's training... He might not be as good as if he were professionally trained but it's really rewarding that anything he does know, you taught him
I just started with Jax a few months ago but he's already learned so much!
So far we're just working on tracking and prey drive and when he's not on the field I try to situate his crate so he can see what the other dogs are doing.
It's adorable when he sees the bite sleeve on the ground unattended and starts prancing around the field With it like he owns it because he sees that's the bigger dogs' reward and get to run off the field with it.