I used to be a fleet truck fitter for new Mercedes trucks in the U.K. and once asked my foreman what is this adblue stuff I'm fitting? He said, horse piss.
I think it will effect VAG even more when they realise their sub companies like Bentley, Audi, Seat,Skoda, Porsche, Bugatti, Lamborghini, Ducati motorcycles and MAN, Scania, Neoplan and Volkswagen Commercial Vehicles marques all interact with each other to keep costs down and profits up and to do that they are unlikely NOT to have shared ways to reduce costs.
I do not think for one minute VAG are the only ones doing this but I bet they are going to bare the brunt of the backlash.