If the vehicle's driving away, how could someone shoot the radiator? It would have to be akin to the Bill Hickok-Dave Tutt shot. I know laws vary from state to state. Here in Michigan, in this particular scenario, deadly force wouldn't be authorized. It wasn't self defense. Don't get me wrong, the prospect of getting robbed doesn't appeal to me either, but that's why I pay an insurance note. I run outside and start snapping caps, I'll be the one in the back seat of a police cruiser.