Not sure if it's a California thing but one thing that has changed a lot in fifteen years are the types of nozzles at gas stations. Here in California all the nozzles are required to prevent excess vapor release and so make a seal on the tank when connected to the car. Diesel doesn't have the same issue so doesn't have this feature on diesel hoses. The result of these requirements are a lot less fuel vapor floating around a station.
I am also in the camp of leave it on. The fridge can barely keep things cold as it is. On rare occasions the flame will go out while driving and that can be frustrating as the fridge struggles to catch up at camp if it is hot outside.
I'm no expert and haven't been around as long as some of the old timers on this board but I have to think the number of times a camper fridge flame caused an explosion at a gas station is probably close to zero and likely because something else was significantly wrong unrelated to the camper.