Yeah, but where does that argument begin and end?
One could easily argue that any design professional laying out the floor plan for a Circuit City should know to place the cash registers closer to the exit, thereby allowing customers to exit with their purchases unimpeded and unharassed.
Just because I enter somebody else private property doesn’t mean I consent to their search, interrogation and seizure of my property, person, and time, no matter who says it.
If showing your receipts bothers you, you have a responsibility to not shop in stores that require you to do so. doing so, like this guy did, shows that his primary motivation was in creating an incident and in suing the store, not in any aversion to showing receipts.