It's funny you say that, the first time Pip pooped something other than a white mess was about a week ago. It was actually a normal, brown poop. I'm sure we were equally surprised lol.
But yes I also agree that petstores have a master plan, however I feel like that would hurt their chances of selling because as soon as someone walks into the store and sees these tiny ball pythons they're going to wonder. I'm sure they encounter plenty of ingorant people though. (like me)