Ethical burdens aside, I only buy animals I plan to keep for life. I find it funny how many snakes are claimed as rescues. And im not implying it in your situation. But if you bought out a collection and kept the stuff you wanted and decided to sell the other animals you should feel no ethical burden as long as your buyer has 100% of the information. However I would have a ethical burden trying to sell them at the price of breedable ball python, especially if you are against the breeding of these genes.