I say again even if you dont like helmets, wear one. In the case you get into an accident with a car, the drivers lawyer will try to make it all your fault or at least partly your fault if you are not wearing a helmet. This will be true if that in no way were you at fault at all, such as in a right hook. Being in the right and then getting screwed by a lawyer in a crash just plain sucks.
This is why on my trike I wear my helmet, have two flags mounted on my seat, and wear HiVis T-shirts. That shuts down all the BS that any crash would be my fault before it gets started. So I say protect yourself from head injuries is some cases, and from legal BS!!!!!