You are correct Ulthar ...
The one thing it effects most is propane, the summer fill of LP is rarely a bargain as LP can expand as much as 5%+ in ABOVE ground tanks. I have a 1500 gallon tank and I always fill mine at the end of winter, and the amount in the tank increases by as much at 5%-7% in warmer weather. I filled mine in March to 75% and now even after some use it's at 82% due to the warming weather. This is why propane tanks are painted white or silver most of the time.
Decidedly true.
Underground storage tanks largely eliminate the temperature fluctuations this is based on. The temperature difference required to see a noticeable effect is actually quite large. A friend of mine had to do the calculations on this for his PChem class when he was an undergraduate student back in the 80's. But hey, Americans rarely let facts stand in the way of some good old fashioned sensationalism and jumping to conclusions.
Who knows how tanks under gas stations may warm up, particularly if not full, plus they're often under black asphalt absorbing and radiating heat, and the pumping process will introduce oxygen - hot air - into the gasoline, and who knows how warm those black rubber hoses get absorbing that radiant heat energy all day long...?
I will say I have noticed, particularly on warm days, evaporation at the pump... you can see it and smell it.