Until they got caught, that is:
This reminds me of the novel I read that was written by an armored car robber. It detailed all the preparatory work they did prior to a heist, and all I could think of was, "man, these guys are smart enough to make good money doing something legitimate, they wouldn't have to work as hard and there wouldn't be an inevitable stint in the joint." Just design the emission system to work. What I'd like to know in the Volkswagen case is whether they were charging customers to refill the DEF tank in their cars, even if it wasn't being used. Now that would really piss people off.