Per my kids' school, Teachers cannot apply sunscreen on the children.
Parents, IF they want to, they need to apply it on their child, before they go to school.
Me, EVEN if I have sunscreen on, that is 50+ SPF, I STILL get tan. And I can get sunburned. Still.
Sunscreen does not mean a person will not get tan.
Even if a person is in the sun on a cloudy day and under shade, they still can get tan and/or sun damaged, because of reflective heat/sun rays etc.
At my kids school and in my State, even if you are in the sun for only 10 minutes, you can get red or tan.
And, with students being outside for recess or P.E. they DO get sun burned, and/or tan.
And it also depends on your skin type.
Sunscreen is not permanent nor does it last for 24 hours.
It needs to be, ideally, re-applied.
Or there are water resistant or sweat resistant sunscreens. But those are typically for 8 hours.