I might lose some results by banning those who allegedly serve known spam-files, but my experience shows, that my search results got far better after banning efreeclub-sources a few times, if only because they can then no longer hinder the dynamic querying, and I only ban search results, where you won't/shouldn't see hosts from the download-mesh.
And heck, I told you, I am playing
This isn't a play-guide for those who don't want to risk losing results or outright losing contact to most sources
Still your information about fake-ips being included is interesting (I only knew about that as theoretical possibility).
And I think checking that hostiles file against the hostiles file in Phex could prove quite effective.
Integrating the spam-file will afaik take some coding, so it might take some more time.