I met the other intern today where I work. He's in a band, and his band has a Myspace page of course. One day all the content of their page - photos, music, 900+ friends - disappeared. They eventually determined that a band member's exgirlfriend had the password and took her revenge. (Hell hath no fury and all that.) Me and the intern puzzled over a legal theory to cover this kind of thing. Trespass of chattels? Is an internet site a chattel? Is that considered hacking, since she had the password? Do they even own the chattel, since the site is free?
Moral of the story: Never give your S.O. your passwords.