Several of my rentals with Avis proceeded like this when I returned the vehicle:

1) Did you fill up the tank?

Yes

2) Rep checks the fuel level in the car

3) Rep prints receipt and hands it to me

4) I question the EZFUEL charge

5) Rep asks to see a receipt for the fuel purchase

6) Rep prints a new receipt

The point isn't that they will take it off if you ask. The point is that you shouldn't have to ask and you shouldn't have to show a receipt. (Maybe not everyone has been asked for a fuel receipt, but I have several times.)

Avis knows the gas tank is full without having to ask you. The charge should be automatically removed if the tank is full. End of story.

Not everyone checks their receipt before they walk away, especially at airport locations if you are trying to make a flight. It's a gimmick to get more of your money.

I have written to their customer service regarding the issue, and I don't rent from Avis anymore.