The whole "detector van" thing is mostly a bogeyman to scare people.
The technology to remotely see what's showing on a CRT is Van Eck phreaking. Not sure over what distance it would be possible (and whether you could target a specific house accurately), also given the diversity in display technologies at current I can't see it being too effective.
The technology to remotely see what's showing on a CRT is Van Eck phreaking. Not sure over what distance it would be possible (and whether you could target a specific house accurately), also given the diversity in display technologies at current I can't see it being too effective.
http://en.wikipedia.org/wiki/Van_Eck_phreaking