I'm a dad of 4 (just putting that out there so there's no confusion) and this morning my dd (17) told me that yesterday, which was pretty hot here (not that that should matter,) she was told by a female member of staff that she had to either wear a coat all day or go home because her top had straps which made her shoulders visible.
Nothing else was uncovered and she was in no way indecent, she was just informed that shoulders had to be covered because otherwise (I know you can see this coming) it was "distracting to boys".
Apparently quite a few other girls were given the same warning that day (probably because it was the first really warm day since they'd been back to school and had all dressed according to the weather) and then a school wide announcement was made.
I've checked the uniform policy and there's no mention of it so I've emailed the school asking for clarification.
If this is indeed a policy that's being enforced I think it's ridiculous that female students are being made to dress in ways to suit male students. If a boy is distracted by girl's shoulders then the problem is with the boy! The messages this sends out just make me smh. It's 2020 and girls are having to think about how their clothes might make boys (and by extension, men) react. Argh!!!