This isn't a harmless little cheat we're speaking of, he actually made a denial of service attack on a server. No matter what was the point behind it, it's a serious offense which should definitely not go unpunished.
What annoys me is that the police reacts with such timely haste when Activision calls in, but if an independent host was the victim of attacks (I've known many whose work has been ruined by idiot teenagers with a few scripts), the police would just tell him/her to piss off.