The issue for me is that these spambots are blurring my site stats. I like to see a realistic number under the header 'who is online'. That is why I block spambots that keep coming back. I also block spambots that absorb too much bandwidth by visiting every page on my site, and bots that request non-existing pages like http://www.mysite.com/downloadfreegames.html
It would be helpful too have a database of the most active spambots, which of course would have to be updated regularly.
By the way, what is a RAC type action?
My question then is why do you allow these bots to register at all?
I am assuming that you are using phpBB2 or am I mistaken.
It is possible to stop their registration completely with about 5-10 minutes work.
The RAC mod inserts an extra field that is compulsory to be completed in the registration. Bots can't read and they just complete what they believe is a normal registration. They fail so they do not get past the registration page. They never appear in your memberlist nor as the latest member in the index.
I have installed the mod on 9 boards so far and none have had a single spambot in over 2 years.
This of course just applies to bots. In my experience human spammers are quite rare by comparison so I would not subscribe to such a list myself. Who knows what the future may hold though.
The truth is out there.
Unfortunately they will not let you anywhere near it!