I have a lot of fun with my local Fry's and their "security checks". In reality all I do is briskly walk past, and wish them good morning/day/evening. Most of the time this throws them enough for the moment. They seem to do the math that they're not paid enough to deal with my shit. But the few times it has been raised as an issue, I've always (of course) properly paid for my merchandise.

I know it's a bit immature, but as a result of those minor confrontations, it always gives me the jollies every time I stroll out with just a "Good evening!"