I'm starting to think there are a couple of different ways to frame the question. I'd been thinking of it along the lines of "my economic exchange model doesn't include that the actors can understand the larger world", which is definitely map, not territory: the exchange model of decisionmaking is simply missing a lot.

One can also think of it in terms of general decision theory - in this case "externality" isn't something missing from the model, but something that the agent doesn't care about as much as the analyst applying the term wants them to.