Saw posters on /r/Truckers complaining that truck stops were taking advantage of situation to gouge for DEF too on top of diesel before someone pointed out that Iran is the second largest producer of urea, the primary component of DEF. They are not happy right now with $5.00 / gal fuel and higher DEF as well.

Worried the administration will use it as an excuse to rollback NOx emissions regulations that mandated DEF usage in diesel engines. They are already not enforcing "deletes" of the emissions systems which is a federal crime.