a photo from Sudbury Valley's webpage
See the article here -- the Sudbury Valley schools talk a lot about "freedom," at least in their promotional rhetoric, but freedom is a slippery concept, especially in philosophy. It's difficult to say that people, especially children, are "free," while at the same time observing how they are conditioned. So, avoiding the "freedom" concept, I see these schools as being about trusting children with a degree of intelligence, trusting that they will figure out the system for themselves and make the right decisions as they see them.
Paulo Freire's critique of the "banking model" of education pivots on an analogy of teachers, disciplinary teachers, with bankers. In repressive schooling, the teacher-bankers make "deposits" of knowledge in the heads of students. Teaching according to the "banking model" is like giving knowledge to students and then treating them like idiots.
Sudbury Valley schools, on the other hand, seem to be treating their students like intelligent human beings from the get-go. I imagine the "free range" educational form to be problematic just like disciplinary schooling, but much more humane.
It also "greases the wheels" that, with the Sudbury Valley model, the students are likely to come from well-off backgrounds, since well-off parents are parents that can afford the tuition. The students, then, are likely to come from families where knowledge is respected, since knowledge is one of the things that determines "well-off" class position.