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Is using the last name of a person without a title an accepted way of addressing?

I always heard people use Mr/Mrs/Miss/Ms before people's names and that is how, I thought, it was done until I watched one of those Harry Potter films in which Malfoy (Sr) addresses Albus Dumbledore as just Dumbledore. I noticed later that even Rubeus Hagrid was addressed as only Hagrid. (I have actually read all the seven Harry Potter books but it never occured to me while reading.)

Is this way of addressing people common and considered polite?