Looking at the video, you can see that the perp is physically fit. You can also tell that he's overly aggressive and arrogant in nature since his car is the one that's parked on the curb (rather than the parking lot). I would hazard a guess that the guy is probably using steroids, and this caused the man to flip out.

I know those guys are just working to earn a living so I don't give them a hard time, but I always ask, "Do you have reason to believe that I shoplifted these items?"  Sometimes I ask them if they know Amendment IV...I know....weird.

Usually, if it's stuff I absolutely know I won't ever need to return (don't think I've actually ever returned anything at Wal*Mart), then I just hand the guy the receipt and keep walking. Now he's stuck with the receipt and doesn't know what to do... does he try to give it back? Does he put it in his pocket? Does he walk to the trash to throw it away allowing other customers to escape?

That's good Todd.  I like that one.

Greeters and security guards can ask for a receipt till they're blue in the face. I say no thank you and keep on walking. Under state law, store employees cannot detain you (stop you from leaving the store) unless they have probable cause, a legal standard that requires evidence of shoplifting. If you don't want to show your receipt, just say no!