TV detectors
There's a signal resonator and amplifier in the back of all TV sets, which amplifies the antennae signal so that it can be used to control the scanning cathode guns. Leakage from this is what is picked up by TV detector vans / hand-held units.
In theory, you could cover your TV in aluminum, but it would be a highly dangerous fire hazard, plus i dont know if you need to cover the front as well or not.
I have no idea if they can detect a TV display on a monitor or not. It used to be if you had a studio monitor, (special monitor that only shows the feed from a video camera) you didnt need to have a licence, since obviously you couldnt watch live TV on it.
If you have a VCR with a tv tuner in it, as most do, that's 'TV reciving equipment' so you need a license.
I dont think there's any way they can pick up a signal from a LCD screen tho.
I used to have a PC tuner card from 1995, which worked once in a blue moon. My stance if they ever bashed in my door would be 'see if you can make it work! If it does, I'll gladly give you double the fee!' Never happened tho.
License warning forms are sent to every single address in the UK that isnt already registered as having a license (something like 98% i think) so there aren't all that many to check up on. Something like one or two in every street, a few dozen in each town.
I used to live in a hostel, which is specifially exempted from the licence requirements, and we all used to get threatening letters all the time, warning we would be sent to jail and so on, which scared some of the more mentally vunerable tennantsw and drove the care manager up the wall (and yes, she repeatedly contacted the licensing authoroties several times to register as exempt. didnt' stop the hassling. )
Now, I've not had a TV in my flat for several years, and I repeatedly get extremely nasty letters carefully worded to stay just this side of the law on illegal exhortation, telling me in big red letters that if i do not PAY 110 quid or whatever RIGHT NOW, I WILL GO TO JAIL!!! Then in tiny tiny print at the bottom is some bumph about how i should write to some dicky bird if i happen not to actually have a TV.
bollocks to that. I keep thinking about making a formal complainant, but dont have the time. I do know there are websites about it, and some old codger MP raised his concerns in Parliament about these theatening letters.
xoxo
tomato