Teachers and Facebook?

In the article Teaching the Facebook Generation it tells us how to many teachers are not able to keep their distance from students on facebook. I agree that this could be bad but teachers know the risk when creating a facebook page. Teachers can always block there personal info from non friends. also they dont have to accept the students request. It can be risky but why should teachers not be able to get a facebok its a little unfair. I think teachers should be able to have a facebook.