It was comical, but also sad, seeing people doing that in middle Georgia (US state, not country) a few years back when we had an unusual (for the area) cold spell with a lot of ice. Very few had scrapers and brushes for their cars to clear them so I was cleaning a lot of neighbors' cars while my own car was warming up.

Isn't pouring boiling hot water on car glass a pretty certain way to shatter them by thermal stress?!

It could, though I've never seen it happen when people tried it. It usually just refreezes and scraping (plus running the car heater) is the better option.

Yes, been there, done that.

Also, don't pour cold water on the windshield on a hot summer day, especially if the car is oven-hot and you don't want to be toasted alive inside, because... well...