Real-world side channels are going to start getting more attention as the technology and techniques for extracting information from EM radiation from circuits (not radios) leaking state improve.
Whats known to the public, you mean. I suspect even the nuttier conspiracy theorists don't have a solid grasp of just what capabilities might exist among well funded secret institutions.
Less impressive than 6 feet, but still impressive.
Software defined radios can be had for as little as $10-20 for simple receive only types, up to several hundred for substantially nicer transceivers. They can also be $1000+ for special applications or R&D.