Could You Modify It 'To Stop Students From Becoming This Advanced?

So what happens when, using Khan Academy, you wind up with a kid in fifth grade who has mastered high school trigonometry and physics—but is still functioning like a regular 10-year-old when it comes to writing, history, and social studies? Khan's programmer, Ben Kamens, has heard from teachers who've seen Khan Academy presentations and loved the idea but wondered whether they could modify it "to stop students from becoming this advanced." This attitude is a natural outgrowth of our decision to operate education as a monopoly. [h/t to Cuz BD]