Well, I am self-interested. Imagining that's a contract, I wouldn't agree with it in the first place because I always do whatever I want. So yes, in that context I am amoral too. However, I would agree to create such a system, even if I am unlikely to honour it, because it seems like something interesting to explore. And who knows, maybe the secondary or tertiary activities that I'm assigned do please me!

Is what you described a minimalized description of the monetary system, where the "selection" process is the free market? In that sense, it is impossible to leave the market, and therefore it is impossible to go against the moral rules because morality would be embedded in causality (kind of like cryptographically enforced rules in blockchain if they were impossible to break with sufficient power). Manipulating market participants would simply alter the selectability, the way people do when they lower or raise prices or create new services and products.

I don't know if I'm misinterpreting what you say haha!