After almost 50 years experience as SLF on types ranging from Super Constellation and DC7C to B777 and A340, I have managed to absorb that:
- you push the metal tongue of the seatbelt into the bit with the handle and unfasten it by raising the handle (though some of the early ones may not have worked exactly like that);
- there is a life jacket under my Economy seat that goes on over my head and is fastened by winding these straps around my waist and fastening them in a double bow, that it has a light that comes on when it is wet, a whistle for attracting attention, and tubes that can be used for topping up the air;
- I should wait until I am outside the aircraft before pulling the red tab to inflate my lifejacket (in case I get stuck in the door/window/elsewhere);
- opening a main door will deploy the slide, but if it does not inflate there is a red tab to be pulled;
- there are floor-level lights to guide me to the available exits, the nearest of which may be behind me (count the rows);
- I should remove my high heels before jumping onto the slide (not sitting down and pushing off), and possibly remove loose items such as spectacles;
- oxygen masks may appear due to lack of air pressure, in which case pull the mask towards me and put it on, securing it with an elastic strap that goes behind my head - and only then look to see if small children or anyone else requires assistance. The act of pulling the mask down towards my face turns on the oxygen flow. The plastic bag does not inflate.
- there are special provisions for small children.
By the time I hear all this I will be settled in my seat, with my seat belt fastened and have reviewed the safety card from the seat pocket in front of me. So if I am reading something interesting I may not give the briefing my full attention. Despite the frequent assertion that all aircraft are different, I may know that I sat through the same briefing on this particular one only a few hours ago. So not all of us who fail to give the briefing our full attention are completely blameworthy.
I have never been in a situation where masks deployed, so I cannot speak from experience on that point. However, it does seem to be a good idea that deployment should be accompanied by an automated message, loud enough to be heard above the noise and in the reduced pressure, containing information on what to do and what to expect. It might even contain an (altitude dependent) segment indicating how much longer the masks will be needed.
It would be nice to have some indication of how hard to pull the mask towards you, but it's a very hard thing to put into words. It might be better if the demonstration could include the realistic appearance of a dummy mask from the ceiling to initial dangle height, with the demonstrator then pulling it down to face level. That would be much more informative than the usual practice of just holding a coil of plastic tubing at arms length with one hand and giving a perfunctory dab of the mask to the face with the other, taking care not to disturb ones hair by actually putting on the mask properly.
One set of questions remains in my mind after all of this, never answered in any briefing I have heard: if the transparent bag does not inflate, why is it there, what can cause it to inflate, and what does it mean if it does blow up?