Uh huh.

Mate, I can hear the squealing whine of a flyback transformer through brick walls with my own ears. I DO NOT miss the days when everyone had two or three of the fucking things screaming away all day.

Detecting the magnetic flux those things produce isn’t magic, tricky, or a cover-up. It just requires a sensitive antenna array tuned to the right frequency.

Now, since the shift to flat panel displays a TV doesn’t announce it’s presence in such an obvious fashion. This makes detecting a TV a much more difficult prospect, arguably not impossible, but not likely within their budget nowadays.