а кто рулит kvirc, чтоб поправить конфиг? там вроде есть встроенная защита:
http://kvirc.net/doc/doc_antispam.html
KVIrc contains a small spam detector, and can help you in avoiding that annoying flood of queries popping up when you join large channels full of lamers.
The spam detector works in a rather simple way: when someone sends you a private message containing one or more special words, and that user has no open query window, so the message is treated as spam and is redirected to the console window or is ignored completely (if you enable that option).