this is basically what I was getting at with the "I might well be a jerk" comment. this sort of thing can definitely be unethical, but for reasons that are unrelated to the general argument I'm talking about.

those reasons are also more straightforwardly accounted for if you're doing consequentialist reasoning. It's a first-order effect, not a second-order one (visible just by looking at how much better off I am vs how much better off you are, without considering which actions are incentivised in future situations), and so a heuristic telling you to account for it is less important.