Did it actually endanger the public? A silly question, however, what was the actual measurable consequence of this cheat? Did air quality become measurably worse during the period of this? Was anyone actually and measurably endangered?

An older car on the road puts off more emissions than the modified VWs, yet older cars are still allowed on the roads.

Laws should be followed, so I am not excusing the behavior, but making it sound like the safety of the public was materially compromised is a bit of a stretch.