True. Although given the effort going into beacons, always on bluetooth (LE) and tracking other bluetooth and wifi clients phones are getting pretty good at te

True. Although given the effort going into beacons, always on bluetooth (LE) and tracking other bluetooth and wifi clients phones are getting pretty good at telling what other devices (and their owners) are in close physical promixity. Apparently it's not uncommon for phones to be able to make sounds outside of the range of normal hearing to use the microphone to detect other phones in proximity. So not only might a watch figure out who is wanking, but also who else is in their immediate proximity.