As a former frequent renter, the arrow is easy and straightforward once you know about it. The fact that it’s standard practice is great- not everything is adopted as widely.
As an aside, my (German) Mercedes/Dodge/Freightliner Sprinter has the fuel filler door underlaps (?) the driver’s door. It’s an clean solution saves a latching system and makes fuel theft that much more difficult when the vehicle is closed. It just strikes me as a great solution: