Sometimes, to access a certain contest, you need to like them on FB. So in order to do that I need a FB account. But the information they require once that is done, is your real stuff. It takes you to another window. It's like if I want to check something out on a radio station, I have to go into their Facebook and it asks me for my FB name.

Same for my city. If I want to do something, I need to be on FB and then I can send them my real information. Hard to explain but easy to do.

As to lock, I simply go into my privacy settings and check marked private, only me, etc...