I can't condone this. You don't mess with someone else's system, that just makes you the biggest douche in the world. I don't care if they shove you into a wall and you get hurt, you simply don't mess with someone's computer. Unless of course they screw with your comp... then they're fair game (also if they break any of your bones, or cause you serious physical harm).
I don't know, doing that just seems childish. Not to mention he could just hire someone to fix it for him after he's done kicking the crap out of you. Just doesn't seem worth it.