It doesn't have to only be about safety. I can't use my MBP 13 on the fold out tray of a coach seat. There are times where a less conspicuous device comes in handy.
A coach airplane seat? Depends on your body type maybe; I've done this with the 14" (and the 16" Intel) multiple times. Just don't set the screen angle such that it'll get caught by anything on the seat in front of you.
