Just another data point: Flew ORD-SNA today (UA crew), and they took the lunch orders front to back, without regards to status (I initially thought). However, after completing the order taking, they went back to someone in 1E and informed them that their initial choice (chicken burrito) was unavailable, and would they still want the other choice (chicken salad). They said yes, and everything went smoothly. I thought this was nicely done by the FA...