With my kids, most of the girls do have pierced ears. Most of the time the earrings were not worn unless they were we're going to a special function, or going out for the weekend to their sponsor parent's home. I have noticed earrings that are worn during some athletic events, that they may be participating in.
I have also noticed that their are a lot of cadets, both male and female, who have tattoos. They have told me that a cadet must acknowledge that they have tattoo(s) to their superiors. What ever you do, do not hide the fact that you do have piercings or tattoos.
My cadets have told me that if a cadet has a tattoo, it must be in an area where it cannot be seen when they are in uniform.
I will contact some of my cadets tomorrow, and verify this information.