You're lucky water balloon boy didn't have a violent response to your confrontation. That's what really sucks about life today - $hitheads like them get away with all kinds of stuff because lots of folks figure that any a-hole like that might get violent with a weapon.
I'm glad it went OK for you and I hope he enjoys a grilling in court while you watch. Maybe you could have some buddies ambush him and hit him with a water balloon while he's on his way into court