The industry is at liberty to alter the way it provides information, it could check understanding after the brief. It could do an interactive quiz on the inflight screen if available. Just because you can't imagine a different way of doing it doesn't mean a different way doesn't exist.
Are you serious or are you just plain trolling? And pray tell, what do you do when half the passengers fail the quiz because they were reading their paper instead of preparing for it? Do you kick them off the plane or do you allow them to retake the test after further study review? Or do you send them off to remedial classes?
Get real, will you?
The airline industry does provide information but this information doesn't seem to be filtering down the right way does it? You sound like a school teacher blaming his pupils when they fail their exams
If the student spent all his time playing footie instead of studying then I'd say the teacher is bloody well within his rights to blame it on the student and even flunk him!
Unfortunately, you cannot flunk paying passengers.