As someone with just a fake-info FB account that interacts with it maybe once or twice a week, I am more concerned by the fact that not having an (active|real) account is also a signal that says (or may say at some point in the near future) a lot about me.
From the link - "Did you login with the facebook app on a smartphone while you were at the hospital? If so, they would have your GPS location at a certain time, when you later upload the photos from your camera, it would have a timestamp, and they could just look check where you had logged in from at that time."
If you are a home owner and this is true, you could possibly be identified -- say for instance posting from home 75% of the time and cross-referencing with certain demographic statistics collected from your browsing history and property records. Would that be legal?