My experience with this plugin is that it constantly doubles people's bans for reconnecting with the SAME steamid and IP, and not just people with alt accounts, causing lots of unnecessary increments in people's ban lengths.
It's kind of annoying, I guess I could use different settings than the double ban length, but eh.
Edit: This person's fork looks like it fixes those issues though.
https://github.com/JunkyBulgaria/SourceMod-Plugins