You always take a risk buying from a shop. That is why hobbiest breeders that you know and trust are so crucial to our hobby. I would go with the snake getting overheated before I would jump to some form of a infectious disease that manifests it self like IBD in colubrids. That is why I make no quams paying a little more for my animal and building relationships with the breeders I want to work with. I am not sure you are being too paranoid but I think you have to take a retail store for what they are and you alway take a risk of picking up something bad from a place that has no quarantine procedures in place, know what I mean.
Chuck
Keep in mind, this is a retail store that breeds their own animals. They just happen to have a store front. However, I do see what you are saying. Being fairly new to the hobby though, I really don't know who is reputable and who is not.
4.9 Balls, 6.7 Corns, 1.1 Black Milk Snakes, 0.0.1 Sand boa, 0.1 BCI, 2.0 Dogs, 1.0 Child, 0.0.? Fish