I did a feature that was never going to film, just all digital, and the re-recording mixer insisted we do reels. I was kinda green then, but I knew a little bit and asked him why, because there was no reason to do so and it created a lot of work for the picture editor. I got the classic "That's just the way we do things here" answer with no explanation. I never worked with that mixer again and that post house has since been shuttered....and it was a BIG post house in LA.