So I’ve just been thinking about privacy, and how everyone’s location can be tracked. Then I realized: What about people who have no permission to enter the country?
Like do they just decide to not have a phone, or do they still have phones and just roll the dice and hope they don’t get caught?
It depends. Physical borders may only photograph traffic for security purposes, no dedicated exit gate. Usually its the entry country that records your crossing, which they may or may not share with the other country.
I’m pretty sure TSA does record people exiting internationally though because people have been caught leaving after an arrest warrant has been issued, even if they made it past TSA onto the flight and into the air. TSA will know immediately if you checked in or boarded your flight.