I think the analysis in this post (and the others in the sequence) has all been spot on, but I don't know that it is actually all that useful. I'll try to explain why.
This is how I would steel man Sir Percy's decision process (stipulating that Sir Percy himself might not agree):
Most bets are offered because the person offering expects to make a profit. And frequently, they are willing to exploit information that only they have, so they can offer bets that will seem reasonable to me but which are actually unfavorable.
When I am offered a bet where there is some important unknown factor (e.g. which way the coin is weighted, or which urn I am drawing from), I am highly suspicious that the person offering the bet knows something that I don't, even if I don't know where they got their information. Therefore, I will be very reluctant to take such bets
When faced with this kind of bet, a perfect bayesian would calculate p(bet is secretly unfair | ambiguous bet is offered) and use that as an input into their expected utility calculations. In almost every situation one might come across, that probability is going to be quite high. Therefore, the general intuition of "don't mess with ambiguous bets - the other guy probably knows something you don't" is a pretty good one.
Of course you can construct thought experiments where p(bet is secretly unfair) is actually 0 and the intuition breaks down. But those situations are very unlikely to come up in reality (unless there are actually a lot of bizarrely generous bookies out there, in which case I should stop typing this and go find them before they run out of money). So while it is technically true that a perfect Bayesian would actually calculate p(bet is secretly unfair | ambiguous bet was offered) in every situation with an ambiguous bet, it seems like a very reasonable shortcut to just assume that probability is high in every situation and save one's cognitive resources for higher impact calculations.
We readily inquire, 'Does he know Greek or Latin?' 'Can he write poetry and prose?' But what matters most is what we put last: 'Has he become better and wiser?' We ought to find out not merely who understands most but who understands best. We work merely to fill the memory, leaving the understanding and the sense of right and wrong empty. Just as birds sometimes go in search of grain, carrying it in their beaks without tasting to stuff it down the beaks of their young, so too do our schoolmasters go foraging for learning in their books and merely lodge it on the tip of their lips, only to spew it out and scatter it on the wind.
Michel de Montaigne, Essays, "On schoolmasters' learning"
If (as those of us who make a study of ourselves have been led to do) each man, on hearing a wise maxim immediately looked to see how it properly applied to him, he would find that it was not so much a pithy saying as a whiplash applied to the habitual stupidity of his faculty of judgment. But the counsels of Truth and her precepts are taken to apply to the generality of men, never to oneself; we store them up in our memory not in our manners, which is most stupid and unprofitable.
Michel de Montaigne, Essays, "On habit"
My suggestion would be to add an introduction. There are many more things to be read than time to read. It's incumbent on you as a writer to convince people that what you have to say is worth the time investment. And you need to make that case clearly, convincingly, and concisely right at the beginning.
For this particular article, you need to establish two things:
A paragraph or two addressing those two points would go a long way towards convincing your potential readers that your article is worth their time to read.
To be even more technical, "Prisoner's Dilemma" is actually used as a generic term in game theory. It refers to the set of two-player games with this kind of payoff matrix (see here). The classic prisoners dilemma also adds in the inability to communicate (as well as a bunch of backstory which isn't relevant to the math), but not all prisoners dilemmas need to follow that pattern.
I’m guessing these are very familiar to most readers here, but let’s cover them briefly just in case.
I, for one, was not familiar with the terms, so I appreciated the explanation.
I was reminded of something similar by AspiringKnitter's post below. There is an event in Science Olympiad called Write It Do It. One person is given a constructed object made out of LEGO, K'Nex, or similar. They write a set of instructions for how to reproduce the object. These are then given to a teammate who hasn't seen the original object, who must use the instructions to reconstruct the original object. Seems fairly simple to adapt to a group setting - you could just split the group into two rooms and have them first write their own instructions and then try to follow the instructions of a partner in the other room.
This exercise and malicious idiot exercise differ in the "when" and "by whom". With a malicious idiot, your errors are pointed out immediately and by somebody else. When writing instructions, your errors don't come to light until your partner's object doesn't look like yours, and neither of you might notice until that point. It's important to notice a lack of specificity both in others (so they don't lead you astray) and in yourself (so you don't lead yourself astray), so it would probably be useful to do both kinds of exercises.
Seconded. Or more generally, a framework for how to put together a good reading list, would be extremely helpful.