Use a credit card for fuel and KEEP the receipt
Take a photo of the dashboard with fuel guage in it and then a photo of the receipt (I tend to misplace pieces of paper)

It's a pain to dispute the charges but that's just how it works

I have been picking up more and more vehicles in Australia that are not really full lately. I find that I drive 20km or so and the guage is creeping down fast.

One tactic I have used, is to drive to a gas station as soon as I leave the airport and fill up the vehicle. In some cases it's been $12-$20 of fuel to fill it to the first click of the pump.

When returning the vehicle I explain this, and have received a credit against the rental.

It's a pain but I refuse to be short changed up to $20 on each rental, and when I am renting once or twice a week it adds up!

There is an easier method with the larger cars

One of the features is that it can display fuel used; just reset this value and then just put in the amount of fuel ( plus a bit to get to the hertz office ) used ; I used to do the fill up just after renting, but find that this works

also, for journeys < 125 Km, the requirement to present a receipt for fuel also helps address this since shows fuel purchased vs km driven

It was billed on my receipt

This just happened to me on a Louisville rental.

$61.00 fuel charge on an $11 + tax rental.

When I dropped the car off I used the express return. Mistake at that location I guess.

When I got the invoice/receipt via email I called and disputed the fuel charge and was told it would be reversed. I got an updated invoice via email the following day and it had the same fuel charge on it.

Called again and was told that the Louisville station had insisted that the car was returned empty. I asked how it could have been empty (when returned) when it had indicated full when I picked the car up and the indicated mileage driven was 124 miles on a compact car?

They indicated without a fuel receipt they could not correct the bill.

Luckily I had charged the fuel stop on my AMEX. I faxed them a copy of the charge and
they promised to refund the fuel charge and associated tax. We will see.

I've already disputed the charge with AMEX so I'm covered both ways.

Crook. All of them.

I have also had this problem at Hertz in Sweden (drop off at Stockholm, express drop off out of opening hours). They overcharged me about 200 sek (just over $30), I went to the pick up station (In another city) to ask why this was charged, they said that it was because the tank was not full. The drop off location was at a petrol station, so we willed it up and drove a couple of meters to drop off point, but as it was a friend that filled the car with petrol, I was not sure that it was 100% full, so I just paid. (Later on he did tell me that he was sure that it was full)

So it seems that this is not limited to the USA...

I've had this problem the last four weeks at the STL airport. Every week I fill up at the station 1000 feet away, and this week even told the agent it was full as she began checking the car in. Was in a rush to catch an earlier flight so didn't get the receipt, as she said it would be emailed with no charge. Sure enough the fuel gets billed every time. I called once and offered to send in the receipt and was told it happens all the time and would be taken off, still haven't see that happen...

Given that this now has occurred on 4 straight occasions I think the thing that really bothers me is the clear policy of fraud Hertz exhibits. It's not an agent error, its a policy implemented to fleece customers and only deviated if the customer presses for Hertz to not defraud customers. Since my rentals are always corporate I'm always challenged as to whether I should just be lazy and not dispute. My guess is this plays perfectly into Hertz strategy, add 10% margin to every rental charging for "service and fuel".

Almost pisses me off to start bringing the better business bureau etc. into the conversation. In the end I don't pay for the rentals, but the practice just irks me.

It has only happened to me once out of 25 or so rentals, so no, it is not a policy that Hertz exhibits. Probably just something wrong going on at that location.