
If the dog or bitch is KC registered then an endorsement can be placed to prevent any offspring being KC registered, but there is no way except neutering to prevent them being used for breeding.
From the back yard breeder point of view they are getting a bitch that they don't have to rear for a year or more, and unless they are breeding more than 4 litters in any 12 months they don't need to be licensed, if they breed more than that and have a license again they are not breaking any laws :(
This is exactly what happened to a neighbours daughter when they re-homed a bitch because their two bitches were fighting, when the younger came in season, a few weeks later there was a litter advertised.