That would be very effective - but unfortunately quite illegal.
Alright, how 'bout one that simply sends the IP address of the user and the name of the game pirated to, say, an FBI server?
The problem with that is that the US has no power to regulate whats put on servers/torrents that exist outside of the country. It may be somewhat effective for those inside the US that pirate, but I think thats a drop in the ocean.