The alternative would be forcing the private school to keep the kid, which is what the public schools do.
I live in the LA Unified School District. One of its students kept causing trouble and they couldn't boot him out. All they could do was transfer him from school to school until finally he killed a fellow student. I always wondered the parent of that murdered student felt and thought. Yes, schools should be able to boot them out, and as for where the kid goes after that, maybe juvie? Maybe a special school for problem kids? Maybe stick him with his parents, who just might make sure their little darling behaves, in order to avoid that fate. But forcing the good kids who want to learn to put up with disruptive kids in their classes should not be an option.
> Maybe a special school for problem kids? <
That’s a good idea. Small class size, with teachers specially trained to deal with such kids.
The urban school district where I taught once tried such an approach. It ended in a complete fiasco, just as I expected.
Somebody (I don’t know who) tacked on a requirement. A parent had to give permission for a kid to be sent to that school. Otherwise, the student remained at his home school - free to be as disruptive as he wished.
Only a small handful of parents gave that permission. The alternative school was eventually shut down.