I wonder what other protocols you could use. Perhaps a WiFi system that looks for a WiFi hotspot with a specific name (easy to do on most smartphones) which the

I wonder what other protocols you could use. Perhaps a WiFi system that looks for a WiFi hotspot with a specific name (easy to do on most smartphones) which then connects automatically? Or just instruct your goons to set their phone's bluetooth name to a particular value and then initiate a bluetooth send to any phones with that name.