Crew asks, I turn off. I do seem to be in the minority though - people do appear to think that closing the sleeve on their iPad, or putting their phone in a bag counts as turning it off. I suspect that it's a load of old guff, as I would be astonished if every plane doesn't have a small number of people who not only have not turned their devices off, but have left wifi, and/or phone signal turned on - and planes don't appear to be falling out of the sky. It actually hacks me off quite a lot though - no chapter, film etc. is that important. No person either incidentally.
That said, while sharing the crews's frustration with the OP, they shouldn't have been using the language or attitude that they did.