George, what could have happened is that they receieved a "suggestion" and absent-mindedly clicked on it. I wish Facebook would not do this, but they do! It happened to me once that I clicked on a 'friend of a friend' - there were several other 'suggestions' that made sense and this person, whom I didn't know, was among them. I recieved a puzzled message "do I know you?". I explained what had happened and all was well. Maybe it wasn't sinister, just random and somebody getting overwhelmed with all the crap, suggestions, etc. that go along with Facebook. Not to mention that if you aren't careful Facebook will go through your address book and send friend requests to everybody - all it takes is a wrong click.