I think it's because they may think that red is not her real hair color and that she changed it to that ...hope I'm making any sence (￣∇￣")
She doesn't care about concealing her identity
(￣∇￣") i get what you mean, just feel is kinda dangerous for her not to do so
It would be more dangerous to conceal It actually. She would draw even more attention by being a strong,only women in the department with an unknown identity. She would draw attention no matter If her identity were known, but the identity of noble gives her protection and makes people feel more at ease because they know what they're dealing with
Why Ianna doesn't change her hair color... i mean a woman with red hair that is super good with her sword is like well known within the school, they can just found her identity in a second XD