What niggles me so much in these turbulence related threads are the righteous types banging on about keeping your seat belts loosely fastened. Whilst it's true that some pax don't do this, a great many do. However, where unexpected turbulence hits, it will always be the case that there are pax moving about the cabin for valid reasons. Therefore, no matter what, in such instances there will always be some pax who get caught out. They may very well have had their belts loosely fastened the rest of the time.