Well, what I was trying to say with the pictures was A) how I got the idea in the first place - I noticed in many cinemas, that the screens had rounded corners, just like film prints do. And B) that it's not a change to the movie itself at all, it's a change to its presentation - exactly like if you went to see it in a cinema which had rounded corners on its screen and then went to see it in one, where they had straight corners - you're still watching the exact same movie, only with slightly different cropping.

And losing picture information isn't really an argument - losing a small part around the edges is not only not altering the movie, it is proper. And how exactly this cropping is done depends on the venue you're in.