Page 83 of Kevin McCurley's book, The Complete Ball Python, states female breesing size is 1000+. Breeding is about healthy body condition as Satomi said. Just because a few people on the Internet state a female should be 1500g + to breed and then it gets regurgitated at great length does not make it a fact.
Comparing it to drunk driving is a little out there. I have never had an egg bound female, and I have bred many females under 1500g with perfect clutches every time. The only time a friend of mine had an egg bound female was a 3200 gram girl. So that just about disproves your theory.
How many snakes have you bred? How many people do you know and can prove have had females die or become egg bound under 1500g?
What do you consider a professional breeder? I have a business license and do this for a living...