And that's a very good reason to not open suspect email. Just like your bank would never contact you to verify info, neither would FaceBook. But it does not mean that FaceBook is dangerous.
Now I'm not fanatical about FaceBook. I think it's a great way to reconnect with friends from the past and share photos with family and friends. I'm not too keen on hearing what someone is doing minute by minute, but it is interesting sometimes hearing the random thoughts some of my "friends" have. I would encourage you to join, Bill. Post some pics. It's easier than posting them here, you don't have to use a separate hosting site for pics. Find some old friends from high school.