Cell triangulation is practically consumer grade technology now
For a while just before smartphones, at least 15 years ago now, carriers were experimenting with APIs that allow opted-in dumbphones to be triangulated (via cell tower) and tracked via API.
For a while just before smartphones, at least 15 years ago now, carriers were experimenting with APIs that allow opted-in dumbphones to be triangulated (via cell tower) and tracked via API.