@ Cheeryguy – apologies – you’re quite correct, it was a single set of steps. It’s been a while since I read the excellent book. However it was the principle of rigid enforcement that struck me.
@SimonS1 I agree with your comment about reading this stuff on the website, safety card and in the briefing. The point that I was trying to make was that I believe that the risk to others should be emphasised and it should also be stressed that stringent action will be taken against passengers who disobey this part of the safety instructions. It probably won’t happen for the same reason that the airlines don’t want to upset the customers by enforcing their rules on carry on baggage!