Hmm, that's an interesting question actually. I've wondered about stuff like that before. In short, no. At least nothing particularly obvious. I suppose you could try checking the number of players in the game to see if it decreases. Maybe check each player for things like IsHuman afterwards. It might actually call GoAI or something when someone drops.
Or you could hack the game, overwrite some code, and put in a code hook that detects when someone drops, or perhaps when someone dies. Not the easiest solution though.
