On Sun, 15 Jun 2003 19:09:26 -0700, Menchi Zh-En WP ebeins@hotmail.com gave utterance to the following:

I have wondered why is it that profilically obsessive vandals, like M and L, can return again, again, and again, and so on for a dozen time or something like that with split personalities (sometimes with inverted sex...). Some admin gave up, some persisted. And the vandals repeatedly defaced some admins' page personally.

For those vandals, are they still given a certain amount of time in hope of their possible reforms? If not, how come their split personalities are still so prolific and continue for at least a while before they stop (presumably banned, for then)?

Because Wikipedia has no way of telling the true identity of someone creating an account. Almost uniquely for internet sign-ups you don't even have to have a verified email address (something that would slow people down a little).

If their IP is banned. Don't they have to switch to another computer?

Only if they are at an institution or workplace with permanent connections and a large network. If they are on dailup, all they have to do is hang up their connection and dial in again. They probably will get a new IP number and a couple of minutes later some innocent person will get the banned one.