The Matter Has Reached the Point That Some Women Participate in Tatbir, and I Have - Jurisprudential Answers - Miscellaneous Issues, Vol 5

Ahmed al-Hasan Response:

A woman may not uncover her hair before non-mahram men, and the justification mentioned is not valid. Even if they believe the passage in the ziyara means that some of the Prophet’s daughters came out with their heads and hair uncovered, if they came out in that state then the enemies had forced them to do so after attacking and burning the tents. They did not choose to come out in that state of their own will and therefore committed no sin. By contrast, a woman who exposes her hair and violates her hijab entirely of her own will is disobeying God, Glorified is He. Her excuse that she intends obedience and worship does not benefit her, for God, Glorified is He, is far above being worshipped through acts of disobedience.