Actually, she does not legally need to ask permission. She can show up wearing her hijab or headscarf if she decides to. Hijab is a personal decision but is protected by several US federal laws. So if an employer or superior has an issue with it, you...er...she can sue the company for discrimination. Here are just a few laws that support a Muslim woman's right to wear hijab.
The First and Fourteenth Amendments of the U.S. Constitution. The Fourteenth Amendment and numerous federal civil rights laws bar federal and state officials and private sectors from discriminating against women who practice hijab.
The Religious Freedom Restoration Act (RFRA)
Federal civil rights law, Title VII of the Civil Rights Act of 1964, prohibits an employer from firing, refusing to hire, or disciplining a woman because of religious practices like hijab.
The Equal Employment Opportunity Commission (EEOC) specifically states that refusing to hire someone because of a concern that customers or co-workers may be “uncomfortable” with hijab is illegal.
And of course, there are case laws regarding this topic. Here are just a couple of lawsuits to follow up on:
Muslim woman sues Disney
Abercrombie & Fitch pays out $71,000 to settle lawsuits over hijabs
The are just a few of the laws. I have had my own problems of discrimination from co-workers. But honestly, it is the customers that pose a bigger threat. I have been spit at, verbally abused, and I have been followed home and physically assaulted on several occasions. I can only speak of my location when it comes to the police department, but here they don't care and sweep it under the rug, despite it being a hate crime. I just don't report it anymore.
If you, or whoever the woman is, wants to wear hijab to work, I say MashAllah! You, or she, gives Muslimahs all over the world inspiration and strength to persevere through all of the crap we have to deal with. But in the end, the law is on our side even if it has to be hashed out in court.