I'm sorry to be callous but you just don't understand how any of this works.

You can't just "not post those things". If we are on good terms I can literally just post "Saw you working the bakery this morning, did you skip your morning jog?" and the system already knows where you work and that you are physically active, no input from you required at all.

Facebook already did this with shadow profiles. Facebook has information about me and I have never posted there, I don't even have an account there.