The principal, uh principle, is unschooling. The benefits are interest, passion and proficiency. The cost is negligible. And the institutions aren't ready for it.
It is allowing your children to learn what they want to learn, and let them move forward as fast, and as varied, as they please. The premise is that each and every child has a natural curiosity and, when let loose, will pursue that curiosity and learn at a faster pace than the traditional school setting will allow.
In addition, each child will find a suitable balance of supporting subject matter to naturally round out his or her ultimate learning experience.
Granted there will be lots of questions, and we should explore these, but at the very least, the one-school-system-for-all model is being challenged. This is a fascinating subject and I hope to delve into it further.
The parents’ role in unschooling, since much of this is associated with homeschooling, is to provide access to a multitude of resources so the child may explore at will. The resources may include videos, nature walks, television shows, books, library visits and the like. The parent will facilitate, balance, buffer and question the child in order to awaken any new interests that already lie beneath the surface.
Say the child's interest is biased toward mathematics. You could seek out resources that make math more fun!
Some structure is also required. Not to hold the child back, but more to ensure that the current base of knowledge is sufficient before moving on to the next level, or deeper understanding.
Obviously, if you haven't guessed by now, the parents or facilitators may need to learn as much, and faster, than the children.