I remember the brief period when teaching internet literacy involved teaching people that any text, photo, or video, uploaded to the internet should be considered public, regardless of how the access was limited at the time of upload. Now, people[0] are buying smart devices and uploading all kinds of stuff without even thinking about it.
To a lesser degree, we see the same situation with Event Data Recorders in cars. They record data that can be used against the user in the event of a crash. Are most people aware of this? I doubt it. Having sat on a couple of juries, I've witnessed how ruthless lawyers can be about picking apart an innocuous action to support the case they're making, whether there's malice/negligence/whatever behind it or not.
Maybe we ought to treat creating data as a special case of "Don't talk to the police"[1]
[0] Lay people, the HN crowd is probably making an informed choice. We aren't the majority though.