Just out of curiosity

[vulcanised]

A few years ago I recall a TV programme where some snoops were in a van with a receiver connected to a dish which was showing what was on various computer screens in buildings that they aimed the dish at.

Never heard any more about that and wondered whether it still goes on, or perhaps it doesn't work with lcd screens which are now widespread?

[mixture]

If it were "a few years ago", I suspect you're referring to TEMPEST attacks which basically focus on making use of emissions from equipment to collect intelligence.

Such stuff still goes on, but these days there are additional tools at their disposal and technologies which tend do be less fiddly to intercept such as WiFi.

As for LCD, although it certainly greatly reduces your emissions compared to CRT, it certainly doesn't necessarily eliminate them (signals leaking from the video cable, reconstructing reflected and diffused light patterns emitted from the monitor etc..).