I know some people I invited to join the forum, they don't use VPN and never before registered on Bitcointalk forum, but when they tried registration they received Evil fee message, and you can image their surprise when they saw they need to pay for that.
This can be due to the fact that their internet provider is reusing shared IP addresses, but it doesn't change the fact that we are hurting good users in process of preventing evil ones.
Maybe we need to think of some better solution and I know this is not easy, one thing could be message that tells new member to try registration from different location, friends home etc.