Violation of free speech - or protecting the children?

Well it's a tough call on this one - a Catholic high school principal has informed his students that they must take down their blogs and other personal online sites like pages on myspace.com and xanga.com. So that begs the question - is he violating their rights to free speech, or just doing what he thinks is right to protect his kids from predators online? It's a tough call - I can see both arguments having validity, but I bet the voices on the side of protecting the students (the principal, his staff, the kids' parents) will veto any arguments the kids can come up with against this new policy.