There is much more risk in buying a wild caught snake. I bought a wild caught from a pet store one time. It showed now external signs of distress or sickness, it actually looked healthy. So, I bought it and it died 3 days later from overinfestation of intestinal parasites. Just be careful. I will never buy wild caught again just snakes from breeders. If you really want to purchase this snake here are a few things that I would do first:

1. Visually inspect the snake and its enclosure for mites and ticks. If it has either...dont get the snake (unless you are ready for alot of work).
2. Ask the pet store to save a fecal sample of the snake or sometimes those petstores just leave it in their until cleaning time. If everything is nice and solid, thats a good sign. If it is all runny....dont get the snake.
3. You can also ask the pet store which day is feeding day and ask them if they can call you when feeding time comes so that you can watch it eat. This is a great way to ensure you are getting a good feeder and any good petstore will say ok. If it does not eat, offer to come back the next week. If it does not eat again....dont get the snake.
4. Check for severe scaring on the skin, scale rot and mouth rot. If it has any of these...dont get the snake.
5. Roll the snake over on its back, if it can't flip itself over....dont get the snake.

Those four thing are what I consider the most important. If there is anything else someone can think of when looking at snakes in a store please post.

If you get the snake, put it in its enclosure for a week, wait until it poops, save the poop, and go to the vet. Get a fecal done and get your vet to look over the snake.

After all of that.....Hopefully nothing bad will happen.