I know that "show potential" mean no disqualifiing marks....but it also is the way BYB's impress puppy buyers.
The OP has said that "all" of his dogs have been show quality dogs, and they have all been fixed.
It's very common for BYB's to tell a puppy buyer that they are getting a "show puppy" or "1 st pick puppy"....meanwhile the "breeder" has never shown a dog.
The sire and dam come from "champion lines"...that also impresses puppy buyers...meanwhile the champion is 3 generations ago.
Would a good breeder not make sure the puppy was sold on a spay/neuter contract when the OP had no plans of showing? Giving full registration on a puppy without any qualifications to allow that dog to breed in the future is what BYB's do.
I've seen some show puppy contracts...the breeder often wants the sun and the moon on those dogs before they are ever allowed to be bred....which is what they should have.
Gina