I've had a different experience where I filled up the tank at a gas station across the street from the facility right before returning the car and I was charged for fuel. Apparently the gauge of that car doesn't update immediately so it still showed below a full tank even though I filled it completely. As soon as I got a receipt that showed the charged, I talked to another representative in the booth and got the fee waived by showing the gas receipt. I wish a more accurate electronic sensor was used for me.