I didn’t think you can wash braids. That’s why people with those long term hair styles are always poking and scratching their head.
Of course you can wash them; and people do. They probably have more access to the scalp than people normally do when shampooing.
What I don’t understand is what a teacher was doing spending so much time on a kid’s hair -taking them out and re-braiding them? . Wasn’t she supposed to be *teaching*?