So under your model, the tankers just drive around, dipping tanks, to see who needs a delivery?

Station staff can also dip the tanks and call for refills as needed. Commonplace.

Fuel is measured as it is sold, so presumably this is the primary system for knowing when they will need a refill.

I would guess the delivery driver dips the tank as a failsafe, because spilling fuel is a Big Deal - whether it's an overflow or perhaps even just filling a tank that is leaking.

(I do agree with GP's point about the administration's need to villainize Iran to maintain whatever support they can for the Epstein war though)