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.
Right? Im pretty sure this is a few years stale and already incorporated in some isps routers
https://www.xfinity.com/hub/smart-home/wifi-motion
https://www.originwirelessai.com/isps-can-do-more-with-wifi-sensing/
https://www.technologyreview.com/2024/02/27/1088154/wifi-sensing-tracking-movements/
https://github.com/ruvnet/RuView
The statement from the article was the unlike previously, they used current consumer equipment, and could uniquely identify a specific person. I believe previous versions could just identify that there was “A” person. I don’t know that all that is true, but it is what the article says, and my vague memories line up.