I've responded to another thread similar to this situation. And I have seen the massive blowback from an "attitude check" arrest.
Not only do I respect the author of the blog, I might have done the same thing if I were in a particular mood. Circuit City goofed, and so did the police officer. The author could have left without waiting for any officers to arrive.
If the Circuit City people knew for a fact that the author was stealing (or committing any other crime), they could have arrested him, using a limited amount of physical force. However, merely not checking in with private security is not probable cause to arrest.
I despise shoplifters, one of whom murdered a Navy man moonlighting as security at Kmart a mile from my apartment last month. The killer was arrested by good samaritans. However, guards and police are required to know and abide by laws, and constitutional protections--like the 4th amendment. You swear an oath to defend the Constitution, not frigging Circuit City's profit margin.