RE: To de-fuel or not to de-fuel that is the question
There used to also be a problem with fuel hoses losing their elasticity and coming off the filler barb or at the klunk. Usually as you pulled up (like on take-off: tres bad). Brass klunks also used to get "gunk" from corrosion fostered by the moisture in the alcohol. Plated ones and stainless don't do it.
Other reasons as above: staleness, moisture absorption, spillage risk.