Hats and long hair: for men only?

I'm going to be posting quite a bit on 17th century horsemanship. Eventually, I will collect all the bits and pieces together for a page (left side-bar).

What interests me about this painting from 1652 is that the woman is riding side-saddle, but in fancy dress. Her hair is long and loose, in the masculine style, and she’s wearing a hat. From what I understand, hats were considered masculine wear; women wore hats riding, because riding was a masculine activity.