I was reading a reddit thread from the other month about a man at a martial arts studio taking his around 7-8 year old daughter into the women's locker room despite being told several times not to due to making women and girls uncomfortable. If anything, at that age she should be be fine in the woman's room by herself, although, he can maybe still take her into the men's room if necessary.
Has anyone ever had a man come into the women's locker room while you were there with a young daughter? Did you say or do anything if it happened?