There's the latest story about the dean who was forcing students to cook meals and run errands for her. She was threatening them with losing their scholarships. Here's a link to one story about it:
There are several high-school level private military schools in the US- most of them boarding schools. They emphasize discipline, obedience and submitting to control by the faculty, and to some degree, by older students (upperclassmen).
This type of school could be turned into a "slave" school- possibly with full knowledge and consent of the parents. It would become a close-knit secret among the students, former students, faculty and parents. If it had a good educational track record, and was very selective as to who is admitted, it would probably work very well.