+1 - After all, they do say that every aircarft is different, thats why It's important you watch THIS demonstration. I always do, and the Cabin Crew appreciate it.
I passenger a lot, and even though I have been endorsed on most of the aircraft I'm paxing on, I always listen. Not really to keep the crew happy, but hopefully to set an example for some of the other passengers. As I look around though, at the regular flyers who've decided that it isn't necessary to listen or watch, I wonder how many would have much idea when the pooh hits the fan.
The QF 30 incident showed that people that did not watch the safety demo, struggled in the emergency, particually being worried that after using oxygen masks, the bag didn't inflate. If they watched it, they would have known what to do.
Actually the comment about the bag not inflating was added to the safety video after QF30. Prior to that nobody had really considered it to be an issue.
There isn't a great deal of flow anyway. It's not like the pressure breathing masks that the pilots are wearing. The idea is simply to get the partial pressure of oxygen high enough to keep people conscious for the few minutes a descent should take...at least a descent from the very high levels.
For what it's worth, at very high levels, the masks are just about useless, as the oxygen has to be delivered into your lungs under pressure. For the pilots, breathing with such a mask is actually hard work. You relax, and oxygen is forced into the lungs, and you have to forcibly exhale.
The reality of depressurisations though, is that it is almost unheard of for the cabin to reach the actual altitude. In most cases of depressurisation, some sort of failure of the system happens, and the cabin relatively slowly climbs. It may reach the actual altitude if allowed to continue, but a descent will almost always happen quickly enough to reach tenable altitude before setting off the masks.
QF30 was very unusual (in a number of ways) in that the cabin so quickly reached the actual aircraft altitude (or very close to it).