I'll add something else to this. I'm flying easyJet later this week, and if the Captain is assertive in insisting that the safety announcements are listened to, then it's another point in favour of the airline.
Many passengers are morons, or seem to lose 90% of their brain power when they get to an airport, and I make no apology for saying so. I have had someone sit next to me who didn't know how to open the seat belt. I have had someone next to me on a JNB-NBO-ATH, as we approached NBO, ask me: "Are we still in South Africa?" When I showed her the map in the inflight mag, of Africa and S. Europe, she asked me : "Is this the whole world?"
When I asked her if she'd heard of 'America' she replied that maybe it was too small to be marked.
I rest my case.