Pat, you're absolutely right about Sally.
As in the USA I think that most responsible breeders here have contracts which can include endorsements. When we talk about endorsements here we usually mean those placed on the puppies at initial Kennel club registration. These typically are 'Not to be bred From'. these endorsements can be removed at any time later in the dog's life. I don't know if you have that system there?
Archaft, I can't see any reason to object to a puppy having it's papers endorsed. Its usually a sign of responsible breeders after all. Its no reflection on the prospective purchaser.
I reiterate all that Kipawa has advised too. I would always advise prospective first time Basenji purchasers to visit Basenjis in their own homes where you can. Derbyshire is not all that far away from me and I welcome you to visit at any time to see Basenjis at home. I no longer breed so have no agenda only to ensure that people know what to expect from typical Basenjis.