[themodelplumber]

Great comment. I was also wondering about detection--it ought to be trivial. I'm surprised that government buildings in places like this don't already have simple sensor arrays up and running, especially knowing of the potential for RF use in espionage (information transfer) etc.

[madengr]

Yes, it would be trivial. These kinds of power levels are probably enough to light an LED with it’s leads bent into a dipole.

Pocket spectrum analyzers can be had for cheap these days.