Yes, I've attended one of those schools. The social science curriculum included some extremely blatant propaganda.

True. This is not usually considered a good argument against voting or schools, although perhaps it should be.

Although it might be hard to sneak into an English exam.

Not really.

"Explain, in your own words, why The Party is a glorious protector of our freedoms ..."

Just kidding, I suppose you could make it easier to grade answers that agree with you higher - "why (or why not" questions where you're expected to go for "why", that sort of thing. And biased correctors would find biased answers more persuasive, I guess ... it would be a lot harder than sneaking bias into a social science exam, though. (And that's a stupid idea anyway :p)