What's the guarantee going to do? You've already brought the dog home. You've invested your time and money to train it. You and your family have become attached to the dog!! Now you find out it has Hip Dysplasia because the breeder wasn't responsible enough to figure out the risks before breeding. What are you going to do now? Trade it in with the same breeder to get another dog that has the same percentage chance of hip problems as the one you've just gone through this ordeal with. Even if it was a full refund, which would be very unlikely, the damage caused is more than the value of the guarantee.

It amazes me that there is a market for dogs like these.