I also run a pretty tight ship on Facebook. Only closest friends and family (13 people in total), visibility to friends only and such things.

Father created Facebook account a week ago to keep up with our favourite sports team. I sent him a friend request but he managed to hide it and didn't find it later. Yesterday he received an email saying something in this style: Do you know these people? A list with 13 people was underneath it and these 13 people were my friends.

Thankfully he knows most of them so it didn't get awkward but still a massive, massive worry for me.

Internet's a postcard, not an envelope.