you can of course report them to their ISP. depending on who that is thay could be kicked off.

there are sub7 "imposter" servers. they appear to the client as a sub7 server but will send false infomation. you can send a screen shot of anything you like like an fbi badge or an arrest warrent. you can tell them to piss off or report to their local police office. i found one here but havnt checked it out:

http://209.100.212.5/cgi-bin/search/...&type=archives

or you could do like most of do and just stop your computer from alerting you to such usless things and know that you are protected from it.