I don't understand this assertion. The two VW diesel (US) automobiles I've owned have had an AdBlue system. One was a base model Jetta TDI and the other a Passat TDI (which I now want rid of).
http://ask.cars.com/2012/11/why-do-some-volkswagen-diesels-u...
VW claimed to have a trick that removed the need for it on their smaller, lighter cars. But that trick was a trick that only allowed them to pass EPA tests.
However, VW added the AdBlue system to the 2015 Jetta TDI -- perhaps because they knew that this was a problem:
http://www.bimmerfest.com/forums/showthread.php?t=765593
On top of that, even though the Passat has an AdBlue urea system, it's still affected:
On the open road, a Volkswagen Jetta TDI blew through the
U.S. nitrogen oxide (NOx) emissions limit by 15 to 35
times. A VW Passat TDI (with urea aftertreatment) was 5
to 20 times the maximum.
So yeah, I'm not a happy owner right now.