In one sense, yes I agree it's a charade, but people are non-rational and often very sensitive to the form of things. To me it sounds at least worth trying.

Pondering this further, I think the biggest problem is finding a way to measure conformity even in the face of people knowing they're being tested for conformity.

I disagree. I think it would have a very good chance to work.

To a perfect Bayesian, the importance of an act is not what it looks like on the surface, but the state of the world that makes such an act possible. Unfortunately (or fortunately in this case), human minds are not perfectly Bayesian.

To the human mind, merely resembling another thing is enough for the mind to form connections and associations between the two. This is why public speaking courses can improve people's abilities and lessen their fears of public speech. Even though people know they're just speaking in front of a class who is obligated to receive the speech well, their mind naturally reduces the anxiety they feel for any future speaking engagements. The mind says "eh, it's close enough. I can do this," just like how anti-conformity training should fool the mind into considering it 'close enough' to real disagreement. Speech classes don't not work perfectly, just like chaos training (I assume) doesn't work perfectly, but it's pretty good.

Anti-conformity training seems practically identical to a proven training method, and thus I rate it highly likely to work.

I think that if you've got a deeply habitual inhibition against firmly disagreeing with people, even a known-to-be-simulated experience of breaking the inhibition can help quite a bit.

Ultimately you know and everyone else knows that it's just a charade, and that really your "nonconforming" is just conforming one level below surface: You stand there and take abuse that you know to be insincere, and then get a pat on the back about it later, just like everyone else did on their turn.

Indeed ... This sounds like an initiation, not a rationality exercise.

Personally, to me it struck me as something I would try on a group of first graders (provided I knew I wouldn't be sued) but not on a group of adults. They know it's just a game, and treat it as such, but nobody's going to refuse because to me that sounds like a very fun game (approached from the right mindset, anyways, and provided you make sure the audience doesn't take it too far. I'd probably hand pick people to "criticize" and make myself a member of that group so I could step in if another was being problematic). So they all do it, and they all think it doesn't matter outside the game, except that since it was so unusual a thing to ask them to do they're going to remember when you tell them why they did it at the end of the lesson, and they're not going to forget it anytime soon. Preferably do it when they would normally be having a "normal" lesson.

Harry's army is about four years too old for that angle to work, so I wouldn't expect much of the "training". I'd expect more from the entirely conscious chain of reasoning that they respect General Potter, and that he has them do all kinds of weird "training" things and an awful lot of them turn out to be good ideas, and that he told you outright that he thinks this is an important thing for you to try to do. But then, that's a conscious chain of thought, and by the time an issue like this hits conscious thought it's already passed all the lines of defense that matter. So I wouldn't expect much of it. But hey, he's already employing a scatter shot approach towards their weirdness training so if this one idea doesn't work out it doesn't cost him much more than the time it took him to plan the exercise.