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.
But… if the router collects the data… it is just a matter of time. The room will stay constant. People will change. And there you have the fundamental information to infer ID