Originally Posted By: RiceCake
You have to be a monumentally ....
No need to get insulting.
I notice all the fine folks in Canada and the Northeast US saying the car won't heat up much when it's off during a fill up. You've obviously never been in a climate where it's 100*F and 95% humidity with blazing sun, like Richmond, VA where OP is from. I moved from that area last year so I know. The inside of the car can easily go from comfortably cool to way hot in the time it takes to fill up, even if you are on a long trip and all the materials inside have had time to cool down. So OPs question has merit on that part alone. Highly inconvenient if you are on your way to the most important interview of your life.
Yes, it's not as safe to fuel with your engine on, and signs warn against it. IIRC the law was originally made back in the day when manual transmissions outnumbered automatics by a huge margin and e-brakes weren't as reliable; this was to keep vehicles from rolling away as they were being fueled. Today's 90%+ automatic to manual ratio pretty much takes away this reason.
True it could trip a code and may interfere with fuel indication. As far as fuel getting on the hot cat? Well, the cat isn't going to cool that much during a fuel up so not much weight to that argument. And I've seen gasoline poured on a hot exhaust pipe and...no fire.
A larger concern is for kids in the car that might not be secured and could put the vehicle in gear, and also the chance that the vehicle could easily be stolen by someone waiting for just such an opportunity; or both at once with another tragic outcome. Of course I've seen too many times when parents leave their car running with kids inside to go into a convenience store....
I'll end by saying that I've left my vehicle running when fueling -- but only when it was 10 below Fahrenheit; as a good BITOGer I was concerned about what I would be doing to my oil if I shut it down after driving 6 blocks from work to the station on my way home.