every now and then the city or the country will have new 'sweeping helmet regulations" and crack down on use but it all dies out after a bit. Massive advert campaigns showing heinous accidents and what not aren't enough. Then there are the people that carry the helmet on the bike, in the basket, and pop it on thier heads if they see a police checkpoint.
I even know people who had friends who died specifically because they weren't wearing a helmet and they STILL don't wear one.
I just don't get it... but then again, if you can't be trusted to look after your own well-being, i suppose you get what you deserve.