I think each store would be different. I am a dog trainer at petsmart, and we have a couple of people who know a little about snakes, but care a whole lot and will come running to me with questions or problems. I always check on the snakes and make sure they are doing ok.
I'm sure there are stores who have people who just don't know anything, or are just there for the paycheck. I would take it on a store-by-store basis.