Re: "For everyone else"
The problem is you may have to pass that area under cell tracking for some unrelated reason.
Every user that turns their phone off (battery out or turned off) near the tracked protest area will be looked at ie you where educated about tracking and wanted to enter a protest zone without your phone on.
Thats the problem with any cell device. A a vast area of use is reconstructed by gov and mil experts every phone is going to be considered.
Powered on at the protest.
Powered off before entering the protest area.
Walking to or with a person who was at the protest site or also had their phone off in a guilty way near the protest area.
The cell use map will massive over a wide area and over time. To catch people arriving early, late, meeting people or walking to or from an event.
Did they steam, upload media? If so what, where and how and to what network, where they given data to stream further way trying to hide the person who captured the true optics of the event for the press and a wider world.