People
Even though parents don't want to admit it, school isn't about what a kid absorbs while she's sitting at a cramped desk, but what happens around and in spite of that.
— Jodi Picoult

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
This claims that the real lessons of school aren't the ones taught from the front of the room. What sticks is what happens in the margins: friendships, scrapes, discoveries, all going on around the lessons and despite them, while parents prefer not to admit it.
Context reviewed