Here's some info:
When you register, the IP that you used when you submitted the registration form is used to calculate your evilness. The more frequently this IP or its neighbors were banned, the more evil is associated with your account. The amount of evil associated with an IP decays slowly over time, but the amount of evil associated with an account does not. You must pay or be manually whitelisted to enable posting on one of these "banned" accounts.
I wonder how big that neighborhood is? I remember reading stories of users registering on the Bitcointalk forum for the first time and they were presented with an evil fee. That is a good way to get rid of unwanted members, but unfortunately it keeps legit people from being part of the forum as well.
Question is, how well does the evility perform under VPNs, proxies, and socks? I guess free VPNs can't be used since most of them would probably have been misused by someone by now.