Some users, however, are able to get around this by using VPNs. Well, Xenforo seems to be pretty adept at finding the hostname of an IP (example: http://i.imgur.com/4DYhPlb.png).
I could try to find all HotSpotShield's IP blocks and manually block them, say, with CloudFlare or IPTables, but that would be difficult or at least time-consuming. If Xenforo had the option to disallow registrations that use an anchorfree.com hostname on registration, then this would be easy.
My suggestion is essentially add a way to deny certain user actions (such as registration or thread creation) to users who have certain domains in their hostnames.
Implementation of this would be greatly appreciated. Thanks for reading.
*Note: I'm not looking to block all VPN traffic from my site, only the sketchy, free VPNs like HotSpotShield (which seems to be the most popular one for ban evading and is also malware), so please don't go all eff.org on me.