At a gas station over the weekend, I narrowly escaped being sprayed by gasoline. The person next to me started to pump, and gas sprayed out instead of in. There was about two gallons on the ground.
Turning around, I saw the truck tanker was actually refilling the station tanks via hose.
Could this have caused some pressure imbalance?
No. The tanker truck has nothing to do with it. The problem was with the car being filled.
If the tanker were the cause, every car being filled at the time would have done the same thing.
Sounds like someone was “topping off” their tank and over flowed their car. This is why you should always put the nozzle back into it’s cradle when it shuts itself off.