Simple...
It is not a requirement it is a custom! Same as men with Long Hair stuff.
http://www.jesus-christ-forums.com/home/viewtopic.php?t=1453
The women who wears it does it out of faith because she wants to do it to please the Lord. If she is forced to wear againist her will then it is not done out of faith and becomes worthless.
All things are lawful unto me, but all things are not expedient: all things are lawful for me, but I will not be brought under the power of any.