What do you about extremely controversial members?

Now here's a question I doubt anyone's thought too much about. What do you do if someone joins your forum who is well known to be a controversial figure in the community and has an internet wide hatedom devoted to them?

Like if someone well known on Encyclopedia Dramatica became a member of your site like Chris Chan (aka someone with a many thousand strong hatedom, trolls after their every move, etc).

Or someone who was a well known but very divisive celebrity, like Justin Bieber or the writer of the Twilight series.

Would you let them be a member and assume best intentions? Would you have the confidence to defend a member of your forum against the likely constant troll onslaught you'd get from them being active there? Or would you get rid of them just to avoid your forum becoming a battleground for arguments?