This is the sort of approach that's utterly foreign to me.
When people in my class started turning 18 teachers reminded us that compulsory education doesn't apply to them any more, so they're free to leave at any time - with appropriate consequences regarding their chances of passing, but nothing else.
They still almost certainly live at home and I imagine there’s an expectation from their parents to finish high school. There’s definitely a big line between being a crappy student doing the bare minimum vs dropping out.
I don't get it. At age 15 I had curfew, but could generally come and go as I pleased. At age 17 I was at times left alone at home for a few nights. This was all normal in my teenage years in my corner of the world.
Why would high school need to function as a daycare? The teachers would definitely rather not have to deal with this on top of the usual responsibilities.