@FTS , the attitudes are just simply different towards wearing a helmet it might be the same in Denmark ,i know it is here. I'm genuinely one of the few wearing an helmet around here (in my town) and people find it odd.
I guess in the Netherlands we are so used to riding a bike without wearing a helmet. I have to confess I see more and more children wearing them. But these are mostly children on their own bike or on such a hang on bike (which can be connected to the rear of the parent bike). I can't remember I have see children in a so called 'Bakfiets' wearing a helmet.
Personally I only wear a helmet when riding a mountain bike, as the chance of falling etc. seems
to be bigger.
BTW one of the hot issues currently in the Netherlands with regarding to biking are the lights. Well it is in my surroundings. In the dark winter and at night it is hard to see (if not impossible) to notice cyclists without (proper working) lights on time. Police increased the frequency of the so called light controls. Often located at sneaky locations were cyclists can't escape their check
In my hometown it is said the fine for riding without lights is about 60 euro.