Its important to recognize that there is a time and place for everything and one must pick their battles. Otherwise all you'll have to show for yourself at the end of the day is your pride and a negative balance on your bank account.
Its also important to see events within the context of degrees you can't just have reflex attitudes and assumptions in reaction to every request that is made of you from your superiors and automatically jump to rascism. , she made no mention of the woman being regularly mean-spirited toward her. Other races simply don't have the awareness of what it takes for us to get our hair straight so she probably assumes she's making a minor request that will allow her to ascend in the company more seamlessly.
You also have to keep in mind what your bargaining position is, when you're working your way up, you have to make reasonable compromises and do your best to fit into the culture of your firm, by the time you get a pretigious position, your repertoire will speak for itself and you'll be in a better position to stray from the norm.
Its not that serious to just wear your hair down more now....she can still reach her goals with rollersetting and satisfy the cultural expectations of her firm a the same time.
I get what you're saying BMP, really I do, but...
I don't know how "messy" and "unkempt" the OP's bun is (I'm still trying to figure out how the simplest and most conservative style in the universe can be called "unprofessional" or "messy", but I'll save that for another thread).
I'm just thinking about being in the OP's shoes. Say, I straighten my hair on the day in question for a company outing not thinking anything of it, but just seeking a change. Up until that time, no word has been said or mentioned regarding my hair. Nothing. All of a sudden I get back to work to hear I'm up for a "promotion", but I need to keep my hair like how I wore it over the weekend for some bullcrap reason to keep the "clients" happy. Yeah, right.
It's like I'm being blackmailed into damaging my hair on a daily, weekly basis to get some "future" promotion that may or may not exist. Again, what if the OP wears nice, professionally styled weaves, wigs, etc. (which wouldn't be a problem in matching her 3ish hair texture) and there's STILL a freakin' issue? It starts off with things like this, then it escalates. I feel she needs to document this conversation and speak to someone at the EEOC. I don't trust company HRs, because they're usually on the side of the MANAGER not the employee. I've heard not to pleasant stories of "set ups".
It's not just "hair" to me. I've spent seven years growing out my natural hair and there's no way I would straighten it to appease someone who hired me with it in its natural state.
Anyway, the OP's decided to change so there's nothing left to be said and I seriously hope she gets this promised "promotion" at the expense of potentially damaging her hair.
I see things differently, but I respect yours and everyone else's opinion that she should conform. I understand the reasons why, but there are still principals involved here. Most black women have afro-textured hair that is different from all the other races. We need to learn to work with what we have naturally. There are beautiful professional natural hairstyles in fotkis and on youtube.
I wear my hair out 99% of the time, because that's how I like it and I make sure that it always looks neat, moisturized and healthy. If it takes two or three products to get it that way, then two or three products it is. My hair will NEVER look busted when I leave the house. I don't just "wash n go". I wash, distribute styling product on sectioned wet hair, style the way I want, diffuse for a few minutes, fluff some more for fullness THEN go. 45 minute routine every THREE DAYS.