Are you SURE they were feeding crickets or where there just crickets in the cage? One of the petcos that I go to has one long cage that is divided. Bearded dragons on one side and ball pythons on the other. While the divider does it's job of keeping the animals apart, it doesn't do so good at keeping the crickets where they're supposed to be. Also, crickets at a pet store are pretty much ubiquitous, all an employee has to do is accidentally drop one box of crickets and they're all over the store. If you saw one floating in a fish tank would you be complaining that the pet store was feeding crickets to their guppies?