Originally Posted by
toxman
Almost every car on the road these days has a trip odometer. Reset it at the beginning of the rental. It will give you the total miles driven and the average fuel economy. Use those two numbers to calculate the actual amount of fuel used and put in at least that much. Keep a record so if you get charged, you have data to back up your claims when you fight it. Easy Peezy.
Thanks, but it's easy enough to tell how much to add. My original question was when will they care. And it seems there are varying answers, some are specific based on on-board sensors and connected cars. Others are less specific, perhaps for cars that aren't connected.
As for "Easy Peezy", I never find having to call in and fight a claim as "Easy Peezy".