From New York Post (tabloid):
Think ditching your cellphone and laptop means nobody can track you? Think again.
Scientists have discovered a chilling way ordinary WiFi networks could work together to identify people with near-perfect accuracy — even when they aren’t carrying a phone, smartwatch, Fitbit, laptop or any other connected device, according to Science Daily. Researchers found that unencrypted signals routinely exchanged between WiFi devices and routers can be used to create radio-based images — akin to a camera — of people and recognize them within seconds.