Not sure why anyone would leave any engine running while filling up. Just using fuel. I shut off my pickup, my car, and yes, even my semi truck every time I fuel. Especially on the latter. If I am stopped for more than a couple of minutes, except in stopped traffic, I shut the engine off. That thing uses 1.5 gallons per hour idling. Add up the multiples of minutes stopped during a day and just idling all thru them, multiply that by operating days in the year, and that can add up to a lot money shoved out of the stacks. And it is one thing to listen to that engine when driving the truck, I sure don't want to stand beside it pumping 150 gallons and listen to it if I don't have to.