The suit, the story and so far the discussion is completely missing the point.
You purchase fuel by the gallon. When it is measured by the gallon and priced by the gallon, you have not been cheated. You got what you paid for.
Now if you want to claim that hot fuel has less energy per gallon, then you have to buy and measure fuel by the pound.
And it is true that your tank full of hot fuel has less energy than a tank full of cold fuel.
But then you have to find someone who prices fuel by the pound.
Some places have gotten around this by simply posting advisories on fuel pumps. Still, we have a valid question of equity here in respect to value received.