Many ARGs intentionally attempt to seem as real as possible, which is part of the appeal. There have been examples in the past where this has caused problems for people (the ill-fated game Majestic being one example). Contrived cryptography/hacking puzzles also show up as hiring screens, etc.
My point is that his mindset is essentially the same: He ran across an intriguing puzzle and tried to solve it.
OK. He should solve the meta-puzzle first. "What is this likely to be, and in what proportion of possible worlds is the outcome of knowing the answer to that question good for me."
I agree. A lot of problems that afflict innocent people in our society can be chalked up to not doing that kind of higher-level thinking - what would be a person's possible motives for setting up this scenario? What are the potential consequences? Am I risking my finances, health, or livelihood by getting involved?
My point is that his mindset is essentially the same: He ran across an intriguing puzzle and tried to solve it.