Back when I ran an e-mail provider, we had this kind of thing regularly. Worst one, though, was when some spammer faked spam in the name of a guy that had previously tried to track him down, with a message advertising child porn with the anti-spam activists name and address. The guy needed police protection and his mailbox overflowed with threats.

It was a pretty stark reminder that you can rarely trust the source of an e-mail, and any counter-measure against suspected spammers needs to be weighed very carefully, because it will be used as a tool to attack adversaries.

Including anyone the spammers perceive as trying to attack them.