There has to be lots of other methods that TV licence dodgers could be caught too. Sky,BT,Now TV all must have details of users that may or may not be available to run licence checks against perhaps?
What about BBC's iPlayer? It asks you if you have a licence before you start to watch but maybe they can run a check on your answer too?
As for car tax, insurance,MOT evaders, the North Wales Police put reports on the likes of Facebook daily about offenders they have just caught so they are running checks but the thin blue line is just that nowadays.