1) If it's that cold out, why wouldn't the condensation freeze in the tank? I've never seen a heated gas tank...
It probably does and won't cause a problem in that case.
2) Most of the really cold places I've seen put 10% ethanol in the gas... this should help dissolve any condensation nicely into the fuel, letting it just run through the system without freezing up.
3) Really Cold also means Really Dry, which should mean little to no condensation. The condensation happens when warm, moist air hits really cold things or air. Unless someone's making out with their gas tank, there shouldn't be much opportunity for warm, moist air to enter.
I Should have been clearer here. I have had it happen to me when the temperature went from -5C to -20C (approx). Plenty of opportunity for condensation to occur.
4) Anyone who has a major problem with condensation should consider using additives (methanol/ethanol) to take care of the problem. These are plentiful and cheap - I believe last time I bought the Walmart version I paid $0.50/pint (clearance after winter last year).
Doesn't refute my point that it can occur and when it happened to me it was a rental car