And then you use a revolving door, the material of which also is part of the cage. So the door is never "open" to the outside world at any point.

The waves are in the 33cm (3*10^8 m/s / 900 MHz) range. If the door is open, they come in. Soon there will be a protocol that allows people mobile devices to be repeaters. Someone standing out the door has line-of-sight (LOS) to a base station, and they forward those packets in to all the people inside the cage. I miss having conversation uninterrupted by mobile devices, but I can't resist the urge to push right up to Shannon's Law--moving the max number of bits with as little energy as possible. Information finds a way!

Innovation, creative thinking that just might save our species from extinction or at least stop the most antisocial "faceless" trend in history...not to mention, save your device from a electromagnetic event.

Humans have survived and thrived this long because of our natural mutuality and desire to congregate Face to Face.