Originally Posted by guv1976

I think that, if you weren't willing to go back to the counter before driving off, I would have taken a picture that showed both the odometer reading and the fuel level in the same photo before you left the lot, and then just purchase enough gas to bring the fuel back to that level. And I would have also snapped a picture showing the odometer reading and fuel level at return. No guarantees, but I suspect that that would have worked.