It's absolutely ridiculous. They ban more accounts in a month than some games have subscribers, and the next day I still can't log in for more than five minutes without getting half a dozen tells and a couple of friend requests from spammers. Blacklisting is useless as they create new characters faster than any normal person can block them, and banning a whole bunch of accounts once a week obviously does nothing when they all crawl back out of the woodwork under new accounts the very next day.

Harsh penalties for buyers and decisive broad-brush action against sellers is the only way they're going to even begin making any headway with the problem.