Do you feel vulnerable if you wear a skirt and heels while out by yourself?

I was in the market today and I came across this woman just shopping minding her own business, she was one of the few women in the market wearing a skirt and heels (office style). She was approached, and hit on by two men and she seemed really annoyed by it. I find myself wearing jeans or pants and longer tunic style tops when I go out by myself. I would like to know if skirts and heels make women feel more vulnerable in some way.