Having driven a fuel tanker for 5 years, the gas that is in the tanks at a loading rack has no ethanol in it, it is pure gas. They have a seperate tank for ethanol. When you load the fuel, is when it gets blended together. It's all automated, and it uses specific gravity to figure the octane of the base fuel, then blends the appropriate amount of ethanol to arrive at the advertised grade/number on the pump.
There is no way you're going to get stale gas coming from the loading rack, because the ethanol is blended as it's loaded into the tanker. From that point it starts to degrade the more it's exposed to air.
It used to be that the vent pipes on the gas station tanks were open to atmosphere at all times. When ethanol started being used the vent pipes were capped with a one way valve to only let vapor out if the tanks were building pressure internally, usually caused by temperature change.
The tankers were changed to 2 hoses, one for liquid, one for vapor. As you fill the tanks at a gas station the vapor is forced back into your truck to be carried back to the loading rack, instead of being vented into the atmosphere, as it was for decades before. As you load at the rack the vapor is then forced into their system, and disposed of responsibly. The delivery, and storage systems are similar in design to the vapor canisters you have on late model cars, they don't want the vapors vented to the atmosphere.
Having been around service stations since I was 16 years old, many things have changed as far as pollution controls from the fuel handling, from pipe line, to fuel dispenser.
