arbitrage

Presumably, "arbitration"--and that's a good point, and with clear precedents in the physical world. Nevertheless, "lawyer-y" behavior hasn't prevented a similar mutual-agreement-based system from flourishing, at least in the USA.

The biggest difference is that arbitrators are applying a similarly mutually-agreed-upon law, where rationalists mediating a non-rationalist dispute would be applying expertise outside the purview of the parties involved. That's where your point about advocacy-like behavior becomes important.