If this is a strict requirement of a money pump, (and I can see the argument for it), it seems like the bases for human intransitive preferences don't qualify as intransitive if ephemeral / insubstantial gains are treated as concrete cases of surplus.
In fact, if it is a strict requirement, it seems like the money pump is a fairly useless model unless agents literally had "hard-coded" exogenous intransitive preferences, which doesn't seem to make it much of a practical worry in AI, either.
The presence or absence of an ephemeral/insubstantial gain in a given transaction is a fact independent of any other transaction. Rational agents with well-ordered values that consider insubstantial benefits not easily viewable to an outside observer could engage in behavior where they traded money for insubstantial benefits in a manner that looked exactly like a money pump to an outside observer. They would also seek ways to acquire those insubstantial benefits in ways that cost less.
Really, though, convincing someone that you have an intangible benefit that they want enough to pay for is simply good marketing.
Intransitive preferences are a demonstrable characteristic of human behaviour. So why am I having such trouble coming up with real-world examples of money-pumping?
"Because I'm not smart or imaginative enough" is a perfectly plausible answer, but I've been mulling this one over on-and-off for a few months now, and I haven't come up with a single example that really captures what I consider to be the salient features of the scenario: a tangled hierarchy of preferences, and exploitation of that tangled hierarchy by an agent who cyclically trades the objects in that hierarchy, generating trade surplus on each transaction.
It's possible that I am in fact thinking about money-pumping all wrong. All the nearly-but-not-quite examples I came up with (amongst which were bank overdraft fees, Weight Watchers, and exploitation of addiction) had the characteristics of looking like swindles or the result of personal failings, but from the inside, money-pumping must presumably feel like a series of gratifying transactions. We would want any cases of money-pumping we were vulnerable to.
At the moment, I have the following hypotheses for the poverty of real-world money-pumping cases:
Does anyone have anything to add, or any good/arguable cases of real-world money-pumping?