In the UK (and elsewhere) most good breeders will fully endorse the immature puppies they sell. I made a HUGE mistake when I sold two puppies to a fellow-breeder and didn't endorse them ..... I falsely as it turned out, trusted her. As it was she later sold both to another breeder in another country. Would I'd at least endorsed them Not for Export!! Lesson learned. If they are all sold Not for Breeding, that protects the breed (should they fall into the wrong hands) and the breeder's bloodlines. It should mean that once the puppy is mature, IF the owner feels they'd like to breed, they can be brought back to the breeder for her to decide whether or not to lift the endorsement.
I imagine the system within the AKC, is similar re limited registration, although our endorsements, of which there are now only two, the Not for Breeding and Not for Export, don't prevent people from showing their puppies. And of course, neither endorsement prevents the animal from being bred or exported - it just means an Export Pedigree, needed to Register the animal with the relevant new Kennel Club, won't be available.