My cousin broke his arm recently... I asked my aunt how it happened, she said it was when he was practicing "parkour" (is that what it's called?... the thing where you run around and jump off buildings and do flips and shit). I shrugged and told her that line... she slapped me.
Moral of the story: be careful where you use that line
Anyway, on one hand I can't support shooting unarmed people laying on the ground... but then again if you try to rob someone at gunpoint, i.e. put someone's life in danger, you've got it coming to you and I don't have sympathy for anything that may happen to you. He'd have to be pretty dumb to think he would get this past a jury though.