>I appreciate many vehicles have a hinged fuel cap that stays attached to the vehicle, but it would seem that the advertising team thought that *all* cars have them.
The most common type of fuel cap in the US is a plastic one that sits behind a door that's released from inside the car. This cap is attached to the car by a piece of plastic and you may find a couple of bits of bent tin on the door that you can put it in while fuelling so it doesn't dangle down and mark the paintwork.
I haven't seen a removable cap for many years, its probably an emissions requirement (leaving the cap off will eventually trigger a engine check warning).