This new refueling option is much better for many renters. As a side benefit the cars will be more likely to be truly full when we rent them, not "almost full" from a prior renter driving 30-40 miles before returning.

If Hertz wanted the "full tank" option to be a bit more fair, it would be billed at the tank's capacity minus ~2 gallons to account for reserve fuel and missing fuel from the prior renter driving it to return etc. It's still a disadvantage because it's so hard to calculate that you'll use 99% of one tank.

If I had extra time on my hands, I'd be tempted to circle a Hertz lot on fumes until the car stalls. I was a local renter, I'd siphon every last bit of "my" prepaid (or free tank with coupon) fuel into gas cans after returning the car.