... it could actually explain how some of the items do work -- not broadcasting themselves per se, but modulating back-scatter to give a really short range transmission for next to zero power.

http://www.cbc.ca/news/technology/engineer...tions-1.4013608

That's basically what RFID tags do...or the NSA with your monitor cable: https://upload.wikimedia.org/wikipedia/comm..._RAGEMASTER.jpg