You could also tell who from the public data has a private area, how long they are in it and when they leave it. You could do graph analysis to find folks on 20k bikes (correlate by zipcode) traveling at > 20mph with other folks that also have privacy areas.

If you find that > 3 of folks in that clique are close together and somewhere else, probably having a group event, many of them may not be in their "privacy area".

Anything that collects your location data is a shtshow when it comes to operational security. Even having one friend with poor GNSS hygiene can expose an entire network of relationships.