Yea...all that van detector crap...forget it. As pointed out below they use paper means: the electoral register etc

Once you cancel you will get a year or so before the harassment starts... an endless flow of increasingly threatening letters from Crapita. I took satisfaction in burning several hundred knowing each one incurred postage and administration and was costing them money.

After a period they might send someone out.
When they arrive and you answer the door all you have to say is "I'm busy" and shut the door again. There's nothing they can really do to that. They will post some more threatening bumf through the letterbox and go away.
And then youre back into the threatening letters loop again...and so on.

Even if you have a " illegal"!!! telly the above will see you right.

I haven't had one in near 15 years or so...
It takes time to get used to the conversations of others still plugged into the TV Matrix btw: you notice their frames of reference, conversational subjects and " opinions" are sometimes really quite strange...don't worry it's not you: it's just their media "conditioning" coming out.

Unfortunately people believe they would be boring if they didn't have an "opinion" on lots of often deeply irrelevant nonsense, but as they lift nearly all these from the box they mostly still are.