On the way back from HKG a few years ago, I had a notable demonstration of this. Because I was planning to go straight to bed, after the seat belt signs were turned off I went to the loo to change. When I got out, one of the cabin crew was standing right outside, waiting for me because she wanted to know what I wanted to eat to ensure that they were able to give me my first choice. They could have just left it to chance on the basis that I'd missed the boat because I wasn't in my seat when they came through the cabin to take orders.