Chuni OVER a dastar is the ideal for women. It takes a lot of consciousness and dedication because it's definitely more trouble.
The chuni worn under the chin and accross to the shoulder protects the grace of the woman. To put it simply, Men have a beard to give a protective energy field around the face, women don't. The chuni provides that protection so you don't attract the wrong kind of energy (it means you are not sexually available). This is not a cultural thing, but actually changes the way people see you and relate to you.