What about 1) false negatives (when they receive it poorly), 2) various consequences of priming, 3) false positives (where they receive it well and everyone in main group wrongly assumes they are alone in their doubts)?

You can totally run things in authoritarian manner, gathering consent in instrumental way and use outside sources (like sales) for validation. But downsides/side effects/intentional features not said out loud are well known and researched to the point where one has to intentionally choose to remain ignorant of them to sustain a different narrative.