No they don't?? I always stick to the correct resolution,and keep the borders if its one of my own rips(not a copy from a bootleg which are always badly cropped). I feel if thats the way the film was produced it should stay that way.
encoders always strip "Black Borders" frm video
As for the source Vs the resolution, what i was meaning, is that the newer glory seeking gang of uploaders haven't got a clue what anything technical means and are uploading 720p movies with resolution's of 720px480(or less when cropped) not the correct resolution of 1280×720 and they really find it hard to understand it when you try to explain it!