Like Kitz I pay by DD, and over forty-four years have never failed to pay the licence fee. Therefore I have never had a problem, bar once. And that arose from my wife being a couple of months older than I. I was the licence payer: she would trigger the over 75 concession sooner. Even the problems of that transfer of licencee was solved with strong but polite correspondence.
Therefore I question, if the need for such ads, arises from waste at TVL, but actually is a consequence of a morality shift in our society, transience of population with some chaotic life styles.
I get a distinct impression that Post Modernism's 'if it works for me, it's right' is the underlying cause of unwillingness, determination to disobey laws including payment of the licence.
Look in on Digital Spy and there are numerous posts, that boil down to, 'I never watch BBC, so why should I pay?" Self self self!
So IMHO to defeat the dodgers another collection system is needed, something like a flat surcharge on council tax with refunds claimable by those who lawfully do not need a licence.