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 don’t know if it can actually see your gait. Might be that your legs are technically invisible to it. It’s just looking at how you uniquely disturb wifi signals. It maybe that your torso does most of that or something.