You may find this interesting:
http://ballpythonbreeder.com/2010/11...-spoiled-milk/
In this post I don't discuss paperwork but I do contemplate the fallout surrounding hets not proving out. Unfortunately, a very large number of people in the business have been on the receiving end of a het not proving. I have. It's a horrible, stomach-turning, feeling. Sadly, 100% of the other breeders I regularly interact with have, too.
In the end the only thing you can do is try to buy from someone you trust. That's so easy to say but so tough to do. It's not fair to say that small, so-called "no name" breeders are not worthy of trust when it comes to hets. It is equally unfair to blindly trust the names that you see with frequency around the business. Due diligence is ultimately your responsibility but at some point you have to take a leap of faith in the person from whom you are buying. It's plausible for a mistake to be made no matter who the breeder is; the real test is how they handle it on the back-end.
Regards,