[peterska2]

In all honesty, there is nothing that you can do to stop someone registering on your site if they determined to do so short of disabling registrations all together.

Sooner or later the person will give up, but you need to have good staff who can keep banning as quick as the person is registering. The only problem is that depending on the determination of the person concerned, this can go on for weeks, if not longer.

Moderation of accounts is useful, but only really if the same IP address is used each time, but then an IP ban would solve than problem anyway. Moderation of posts by the registered users group is also useful, but it isn't really going to be suitable for active sites that get a number of new registrations every day.

(Oh and I know the exact member type you are referring too here)