I've done that too. Here though sometimes it's colder, much colder when I find the door is frozen shut. Pouring hot water in frigid temps means I have to clean it up after, to make sure none is left behind to only refreeze instantly.
With a plastic card ready (I keep one at all times), I'm all done in about 1-2 minutes, and can safely shut the door when done filling up. And I can do this anywhere, anytime.