Ok. As far as I can tell: when a player gets banned for multi-accounting his/her IP address is blocked so that they cannot make a new account from that IP address. The way I see it- they could make an account from a different computer and use that account on their normal computer (the one that would've been blocked). If I'm wrong then please correct me. I suggest that once an IP address is blocked, no more turns can be taken from there. Having a pernament ban on an IP address may affect internet cafes and the like, but I remain convinced that it will do more good than harm.
The ways of the hunters are not public knowledge. Basically, no one knows how players are blocked from the site. Yes, hypothetically if I got permabanned, then moved to a different state or country with a new computer, it is unlikely that the hunters would catch me unless I told someone. Is the system perfect, no. Is it the best that people could come up with, I think so. Most users are given the benefit of the doubt on a lot of issues, and people are given numerous chances. This is to ensure that no one receives an unjust punishment, especially people who have not done anything wrong.