Most work places won't hire you if you have many visible tattoos or many facial piercings. I agree that she should be able to look any way she wants, but I think her employer wants more "professional" looking employees. If you think about it, you wouldn't go to work in an office with flip flops and short-shorts or a bikini. This hair changing thing is just an extension of that idea. I'm sitting on the fence here because both arguments are valid. I'm glad you brought this up!

Oh, and I've dyed my hair blue before. Brunettes beware: not bleaching your hair and then dying it blue is nice at first-- after a few washes it leaves an ugly green stain!