Nothing. Of course I'll be tempted to set things up so that those that matter to me have their problems solved. That's unfortunately human nature, that's what happens now (people can game distributed systems too), and I have no idea how to design a system that would be gaming-proof and perfectly egalitarian.

But even assuming that some people will abuse the system (as they do today and we still live with it), it seems plausible to me that the economy would still run better if everything was driven by global optimization algorithm fed with real-time data.