Apparently, even if you set "photo's that are tagged of you" to be friends-only, that doesn't set the actual photos you post yourself to be friends-only.
As I discovered, when a student of mine came up to me on Monday night and was all "I saw your facebook profile, I can't believe you had dreadlocks! Mad respect!"
Later that day, another student of mine (who is friends with the first one) friended me on facebook. After some thought and editing of my profile, I added her back. Why not? There's only 2 weeks left to the semester. If something goes horrible wrong, that's just lessons learned for next time.
Yesterday I found that student #2 had sent me a lovely facebook message, that just totally made my day.
You are teaching, by far, the best class I have had all semester-- Not a night goes by with out something hilarious happening and it actually helps me to remember things! You should here the pow-wows that go on before you arrive!!!
So it seems this facebook-friending thing is working out in my favor. :)