Well, my hands up - I only take it off if I'm getting up (toilet, stretch, getting things out of overhead locker). I think your assertion that it is a low number is countered by the small number of pax who are hurt in these types of mishaps. Therefore, I'd assert that most people heed the warnings and stay belted.
Lindsay - I believe you are a moderator so I will say this very carefully. I believe that very few people on a long haul flight walk in, sit down, belt up, wait, stand up, walk off. I am probably a bit more of a fidget than most, but I would be out of my seat between 1 and 4 times on average. I only do this when the seatbelt sign is off and I always fasten my seatbelt when seated regardless. I hope I am clear.
There will certainly be a number of passengers who were seated and not wearing their belts. How exactly would you ascertain who these passengers were? How would you prove that they hadn't just sat down or were about to stand up and therefore had a legitimate reason for not being clicked in when they were suddenly thrown against the ceiling?
In other news that some posters have failed to pickup :-
Qantas is not a defendent in this action
The plaintiffs include 2 off-duty Qantas staff
"Passengers suffered spinal, head, neck and chest injuries from being catapulted into the overhead lockers. Others lost teeth, tore knee ligaments and suffered serious cuts and broken ribs, feet, ankles and hands in the incident." -This is not turbulence, this is a faulty vehicle
Oh and it
is "vexatious" not "vixatious" - if only every other poster on this thread would put their hand up and say "I was wrong".