Exactly, if your kid has an account, and she identified her mom, facebook will think her mom is your wife if at the same address. Those connections start to add up, add in they copied linkedin, your phone address books, email accounts, etc.
I try to do this and it _seems_ to be working okay. Facebook has not given me a correct/interesting recommendation in ages and google thinks I'm a different age and various other things that are not true when I look at their collected information.
