Hahaha!! That was pretty funny.
I used to work as a store security guard (for about three years) and these guards don't have a clue. They're not allowed to stop anyone if they (or any other member of the security team) haven't seen the approach, selection, and concealment of the item in question. To try to apprehend someone just because an alarm has gone off is moronic - if they get a false arrest on their hands they can be sued for up to £20,000. There's nothing you can't tell me about store security.