It is my understanding that the cars are compliant when being tested - and only when being tested. Not during "the first couple of hundred kilometers." Do you have a citation? I can't find one.
The wording I read implied that they work correctly when they are fresh off the lot, and kick into better performance after they have been driven enough that any testing has been done. Can't find it now, but this is consistent with my own experience (8.5 km./litre of fuel for the first couple weeks in the city, then suddenly a jump up to 13). Also, someone I do business with who was a VW dealer in her last job told me that they all noticed the diesels had brutal breaking in periods, and were always reassuring customers it would be okay after a week or two.
Even if you're right and it was about detecting the testing conditions, the cars still complied under those conditions, so my point stands about the issue being only programming.