QUOTE: "My understanding is that the average alcohol level of an AS owner is too high for the urine to be used as DEF."
Ikpills, while your information is correct for summertime conditions, the reverse is true in the winter.
Just think about it: Airstreamers won't need to use No 1 (kerosene blended) fuel grade in freezing conditions anymore. That is, IF they survive the fill-up procedure. (The caveat "don't touch the metal with your tongue" applies to other moist appendages as well.)