If the chess engine dies or is killed while on ICC, xboard does not disconnect the ICC session. It remains active and can still accept matches, all of which it will forfeit w/o making any moves.
This is a problem because there is a bot on ICC that detects early forfeits and will then block the program from playing rated games. Unblocking it requires an admin to intervene.
I think xboard should drop the ICC network connection if the program dies.
--Jon