Best (worst) I saw was someone throwing hot water over the windscreen and it immediately freezing even thicker than before, as well as making the driveway like glass.
Is ths really true Snapper? (I don't mean to be rude or anything

)
I'm strictly a warm water chucked over all windows man. Straight in the car and crank up the heating. If you put the washers on, the water on the windscreens won't refreeze, it'll be washed off, surely?
In my experience the "scrapers" are very conscientious at scaping bits - even quite a bit - of their cars, but leave huge and unpredictable blind spots where they can't quite be assed to get to.
I've driven for 27 years and never had the luxury of a garage, so I've de-iced with warm water for some time now. I'ts never cracked my windows and I've never had a problem with refreezing.
I watch my neighbours "de-ice" a porthole in the front windscreen and cringe to myself. At least I clear all my windows.