That's an interesting way to investigate how much public policy surrounding schools is actually focused on student education. I think you'd find that there would be significant fear around crime in an environment that already has a heightened risk of riots. For younger students the debate would shift to burden of additional childcare.

That's been a thing for a long time. "Hitzefrei".

In Germany that's already a thing afaik

Since when one learns at school? You go there, listen some guys and then go back home and there the real learning happens: when you sit down, alone, facing a blank paper or a problem you need to solve based on the notes you took while at school.