When I was in sixth grade (in a parochial school) we were 'schooled' prior to summer break, that we should NOT wear sleeveless tops. Boys might see too much.
Did I ever say how much I thought these nuns were out of touch.....
Mind you, during the school year we wore navy uniforms, bow ties on the peter-pan collar of the white blouse, brown shoes & socks.
I remember a hot summer day, Mom sent us to school in summer dresses (that she made) the nuns were NOT happy!
Made my younger sister cry, that's when I was NOT happy!
Today, I'm of the mind uniforms would be helpful for school. Takes the, 'can you top this,' out of their daily concerns. Many waste too much time on what they are going to wear.
I'd give them Fridays off, for freedom of expression ;))

DO SOMETHING!