in reply to A (highly) "ethical" use for for Perl
If it's cool to you then it is CUFP. That's just the way art is. Some like it, some don't.
Why did you choose to fork instead of maybe trying to nice down his processes as low as possible? You could even add that to his .profile or add an if to the system wide profile. Instead of forking you could gobble up as much memory as possible then release it on his logout? Or finding their ip address and flooding it with useless udp packets? I ask because slowing the entire machine down would seem to cause you problems as well as him...
Has it ever gotten out of control and overrun your machine? Just wondering :-) Hope your friend doesn't read perlmonks.