We aren't allowed to wear hats or sunglasses either, the sunglasses you can get a note for you to be able to wear them in class if your eyes are sensitive. They don't open the windows in the classrooms so we have big black shades and overly bright lights to compensate. Needless to say I sport sunglasses.
No, the teachers don't have to adhere to the dress code, I remember in 6th grade when I was going through my chubby stage my pants had just slightly fallen and you could barely see tummy and a teacher in an incredibly short skirt told me that I needed to pull my pants up or I'd be going to in school suspension.
I intend to send a letter to administration again because I don't have money to buy leggings for every dress in my wardrobe and I'm not going to be uncomfortable in jeans just because my maxi dress is too provocative.