Okay, I grasp the concept more clearly now.  Fidelity bonds come into play when there are takers and makers, such as in Joinmarket.  The method to establish provable identities within a decentralized network involves locked value.  An attacker cannot generate identities without first paying the corresponding amount of money.  In WabiSabi, this process isn't necessary because there are no distinct roles of takers and makers; each participant pays for their own inputs and outputs.  Correct? 


I still don't get how this stops sybil attacks or makes them less likely.  Imagine Alice registers input A, and the coordinator registers their own inputs B, C, and D.  Now, if Bob and Charlie want their inputs (E, F, G) mixed together, but the coordinator refuses, how can Alice be sure the coordinator isn't sybil attacking her in this situation?