i thought once upon a time in mexico was shot(forgive me, but i'm not sure of the exact specs) originally on what may be considered the 1.85:1 ration, had the top and bottom cut off to give it a 2.35:1 ratio for theaters, then had the top and bottom restoed for the DVD. i'm probably wrong but i thought i heard that somewhere.
also, directors may shoot movies with DVD in mind. for example, stanley kubrick, i believe, figured his movies would end up having a longer life on tv so he framed most things so they would look fine on a 4x3 screen.
personally, i think many things factor into a movie. watching a lousy movie in it's OAR doesn't make it any damn better. and i'm not a big stickler when it comes to OAR. if, maybe, a little gets cut off the sides and it's director approved and it really doesn't take away anything from the movie, i'm sorta ok with it as long as we're still talking a widescreen version. p&s, though, forget it!
I don't think most people give it much of a thought either. But when you're going to buy a movie, the general desire is to get the best and fullest representation of the original work.