I'm not an RF expert, but it sounds like it would be transmitting an empty carrier wave, not a real signal. Think of it as a big light source and the passive transmitters as mirrors used to flash signals back and forth with reflected light.

(Of course you'd also need a traditional wifi router for everything to connect through, and you might as well build that router into the same shell as the emitter thing, so it gets confusing. But the basic carrier wave wouldn't necessarily carry a signal.)