Scientists in Germany have demonstrated a startling new form of surveillance: identifying people using nothing more than ordinary WiFi signals. By analyzing how radio waves bounce around a room, researchers can effectively “see” and recognize individuals — even if they are not carrying a device and even if their phone is turned off.
I can totally believe when it tracks a person it can tell when the same person walks by again later. But matching people with their actual identities would require a database of wifi scan data that simply doesn’t exist yet.