The Plug-in prevents 100% of bots registering on my forum, but I only get between 30-50 attempts a day
If you want a free 1.0.7 FoolBotHoneyPot, message me (start a conversation) and send me your email address (I'll give away 10 copies)
The plug-in doesn't need to look up the ip/email address/username to check to see if it has been detected before, it simply tricks the bot (which is why it should be more effective than looking up banned bots, not all bots are logged).
By default Xrumer fills out all the registration fields, failing that, some bots just target XenForo and fill out the expected fields. However, with this plug-in, the standard fields "name=email, name=password, name=username..etc" are no longer required, in fact they are hidden in various ways, the order of the fields are random, the real fields are now renamed with uuids, the uuids will be different for every forum install, and if any of the hidden fields are filled/changed, the bot is stopped from registering and the attempt is logged (displaying what hidden fields they entered in the ACP)
It's a free version, so you can always uninstall for what ever reason
(This plug-in is not to resell / give away to anyone else, its also does not stop human spamers)