I once showed an UHNWI what information I could dig up on them, their family and so on in a couple of minutes starting from a single 'checkin' on FourSquare. They were so shocked that it was hard to believe they had been utterly unaware of this right up until that moment. The next couple of days were spent on reducing their information footprint to something manageable, making sure that children were no longer visible and/or easily traceable and so on. Today you can barely find that person even if you know they exist.

If you don't actively manage your privacy you are very likely leaking information that you do not wish to be made public.