Been pondering this all day
As plenty have said, ethanol absorbs water. Calling it hydro, or hygro is really just nitpicking. So the answer to the second question is wrong although you can quibble and say the ethanol doesn't cause corrosion, but the water it absorbs does. So dry fuel is ok, but give it a few days and it won't be dry.
Got my doubts the advice to store a car with a full fuel tank is right as well. Car tanks breathe (and need to) so the fuel will absorb atmospheric water. So the more fuel it contains, the more water it can absorb. Plus, the best way to start a stored car is to sling in some fresh fuel from a sealed can - but you'll not be doing that if the tank is full already.
