From the UK Sunday Times...
Question: "Like many sixthformers I have a Facebook account. Some of my friends have created groups which refer to our school; none of these groups is critical of the school. Our teachers spy on us using false profiles and have told us off for creating these groups. Can teachers spy on us and then discipline us for these activities?"
Answer: "Depending on the privacy settings, Facebook groups can be viewed by anyone accessing the site. What you write could in effect be for public consumption. If the comments posted reflect badly on the school, then the head teacher can, education lawyer Jack Rabinowicz tells me, take action to defend the school’s reputation." (more)