Imagine a spy working for a government, a multinational corporation or a wealthy individual. The first problem is locating the target. That is easy, since the network locates everyone with a "smart" phone in order to optimize transmission power. Your beloved little device therefore identifies itself to every cell tower it encounters. The network knows where each of us is at all times.
At a demonstration, the police report one turnout figure, while the organizers have no qualms about claiming another—which can sometimes be up to ten times the authorities' figure. Yet if we want to know how many people attended the demonstration at any point, exact figures really do exist. We need only determine how many people whose phones registered with several cell towers near the beginning of the demonstration were still registered near the end. We can even tell how many people slipped away! Admittedly, a few holdouts do not have phones, while others leave their precious devices at home as a precaution, but they are very few… More problematic are those who own several devices, though a little sweet-talking should persuade the operators to identify them. Want to know how many people work at a particular site? No problem: the same method will give you exact figures. Of course, the relevant public authorities will not use these data to improve facilities or transport. Foreign powers and competitors, however, are interested.
It tracks you all day long