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 think so. Drywall is fairly transparent to GHz, but I guess depends on if your home is made of sticks or something sturdier. People reflect better, which AFAIK is what this technology is highlighting.