Thanks, but your suggestions are not what I am looking for. I want something like what ProDiigy proposed, but it must be accessible to all players, not just the admin.
What I want to do is to use the /voteban and /votekick commands using the cheating player's clientid (which is a number between 0 and 11 for a twelve-slot server) as an argument. At this point, the clientid shows up periodically in the IW4 Console when the message "*** can get packets from client ***" appears.
Any ideas?