Yes, but it isn't winter ALL year long, you have July 4th there too, right? Seriously, when I moved to VT 25 years ago, I was told that it is best not to let it get below 1/4 for the reason you cited, and in the winter I have always done that. Never had any gas line freeze-ups. I the summer I generally let it drop to about where the fuel light would come on soon.
You were lucky, plain and simple. Every person I have stopped to rescue on an isolated road in Manitoba or North Western Ontario at -30 F or colder had their tank at 1/3 or less at the time of the freeze. Since I have heated parking and don't do that sort of driving anymore, I'm glad I don't have to worry about it. BTW: the Toyota dealer I purchased my Prius from also recommends keeping the tank at 1/2 or more in winter.
Lucky, I guess, because it rarely gets to -30F here! Mind you I HAVE heard of people locally having gas line freeze ups. I wonder, with the bladder in the Prius's gas tank, if condensation would be less of a problem in any case.
That's a good question. If the bladder is the same as aviation fuel cells used on military rotary wing aircraft, it may very well prevent condensation issues. Toyota also approves Ethanol gas, which will also dramatically reduce fuel line freeze. However, I've noticed my average fuel consumption go from 5.2 l per 100 km to 5.5 while running Ethanol gas.
Here in the Netherlands there are no pumps with autofill feature. Only some of the BP filling stations offer this for diesel pumps and some of the large Shell/Esso filling stations close to highways have special diesel pumps for lorries with this autofill feature. However in Germany, Sweden and Belgium (and a lot of the other European countries) it's fairly common to have this autofill feature.
