[scotty79]

In Poland there is a law that you can't run engine in your parked car for over a minute (if there are houses nearby). If you do, you can get a fine. It is considered excessive pollution and noise generation.

And we get winters where temperature drops to below -25C

It's not super strictly observed but people are concious of that and try to keep the defrost time to minimum rather scraping the ice physically than running engine for 10 minutes so the can just push off the slurry.

[iggldiggl]

Generally I'd agree with that and I never leave the engine running just to save myself the bother of scraping (and ideally I've remembered to cover the windscreen with a plane the night before so I only have to scrape the side windows), but I'd make one exception: Sometimes the weather conditions are such that the windscreen immediately starts icing/fogging over again, in which case you really need to leave the motor running at least two or three minutes for the heater to at least minimally start working, so you can actually see where you're going.