Hats are commonly worn in Oz because of the sun. They are a required part of the school uniform. Lots wear them to weddings and church but it is not considered compulsory. However, when I lived in England it was considered quite necessary for church and weddings - and of course the woolly sort to keep the head warm. I prefer to wear a scarf on my head and don't think that it is something most people would bother commenting on - you either wear it or you don't...personal choice.