A sourcing leader obtains preconfs from competing preconf providers, so the existence of a sourcing leader should not hinder price discover for the providers themselves. The sourcing leader himself could of course offer bad prices to the end user by pocketing a large margin. In that scenario, the end users who are consistently overpaying can switch to another sourcing leader. In that sense, sourcing leaders compete on a different level: They are chosen by a user for a given period of time, and during that time can thus provide (almost) 100% guarantees, but users can choose another sourcing leader later if they are unhappy with the outcomes.