Thanks to all for your contributions to this thread. Let me say upfront that I always have my seatbelt fastened tightly unless I'm on my way to/returning from the toilet, or accessing the overhead bin.
At first I put 100% of the blame on those not wearing their seatbelts. But I now have a developed different opinion. As I understand it from comments by
@Mattg and others, SQ have a policy that cabin crew are permitted (required?) to continue service while the seat belt sign is on (only restriction being that they stop serving hot drinks?) and they walk around the cabin, etc. If that is correct (and I have no reason to doubt Matt and the others on this thread), then SQ is, IMHO, responsible for the injuries to the cabin crew. Are they not responsible for providing a safe workplace?
Furthermore, if the pax see the cabin crew walking around, continuing service, then
perhaps they can be forgiven for thinking that "it can't be too serious". If they then leave their seatbelts unfastened, is not SQ at least partly responsible for creating/promoting/allowing this potentially dangerous situation to develop and continue?
Again, I always keep my seatbelt fastened. But I am beginning to see why some don't take it as seriously as they should; and SQ (and others) have, as a minimum, contributed to this situation.
Perhaps a class action for negligence is what is needed to ensure that airlines take a more responsible attitude to crew and pax wearing seatbelts? Unfortunately, it would also probably result in some airlines just leaving the seatbelt sign on for the entirety of all flights so that they may have some legal protection.