if I'd had something on me that I could've swung at him and done him some damage as he ran past then I would've given it a shot.

Yeah, and after he got out of jail (in the unlikely case that he actually ever got there) he wouldn't bother coming after you to do you bodily harm. Instead he'd get a lawyer and sue you for the damage caused by the injuries and the mental suffering you inflicted upon him.

And he'd probably collect. Even if he didn't win the suit, you'd be out thousands of dollars in attorney fees defending yourself.

It's analogous to the idiots who insist on driving right at the speed limit in the left [passing] lane thinking they are doing a public service in enforcing the speed limit. Law enforcement is not your responsibility. I tell the left-lane bandits that until they have a car with lights and siren and a nice shiny badge to go with it, they have no business playing policeman. Nor would you in the situation you described. Leave it to the people who get paid to do it.

You did exactly the right thing.

tanstaafl.