I had a mishap at the gas pump

[Steve #1]

Originally Posted by Steve #1

Now there is a reasonable answer to the question.

Why should you turn the engine off? It prevents the auto shutoff from working properly.

After giving it some thought, this explanation doesnt even work for me. In order for the running engine to create negative pressure, the engine would need to be consuming fuel faster then the pump can pump it in. Even the most thirsty engine isn't going to be using a noticeable amount of fuel at idle.