Hi there. First, I did want to say that I really like this plugin. Lots of useful stuff that has helped me to secure my WordPress installation.
I just wanted to briefly mention an odd error I experienced using the above function. Not having seen it before, I tried using it by checking the box and clicking "Add Host and Agent Blacklist". The first couple of times, all I got back in response was a blank page with nothing more than "Security error!". I then tried it a third time and then was unable to access either my site or the admin interface - just got 403 errors. So I ftp'd in, deleted the plugin, and deleted the Better WP Security lines from my .htaccess file and was able to access.
However, when I tried re-installing BWPS, it was not possible to deselect the "Enable Default Banned List" setting. While I could reinstall the plugin, when I tried going to that setting to deselect, the moment I hit save, I'd get a 403 again. I could recover by leaving the plugin in place and editing the .htaccess file. Everything seems to work fine so long as I don't try to update any options in BWPS. If I do, then boom, 403 again.
I'd very much like to continue using the plugin. Anyone have any suggestions? I imagine there's a setting in one of the MySQL tables I could change through phpMyAdmin. If anyone knows where I might find that, or any other suggested fixes, it/they would be most appreciated.
Tried searching the forum for other notes on this but didn't seem to find any. If this is something that is worth looking into further, I'd be happy to provide more details to the extent I can.