Did you know that it is illegal for a dealer to supply a TV card and not
record the buyers name and address and then pass this information on to the
TV Licencing authority within 28 days?

Similiar applies if as a dealer, you sell a PC with a TV card installed -
new or secondhand.

Information extracted from: http://www.tv-l.co.uk/index_frameset.html
Section :- TV Dealer Information

So, if say you bought a TV card from PC World, paid cash and they did not
request your details, an offence has been commited.

Before you say it -
Another useless fact to fill up the grey matter with!