In mediation, other party gives mediator false information.mediator becomes arbitrator. what are pros/cons?

Answer 1

Mediators are not arbitrators. In fact, the codes of ethics for almost every mediation school prohibit the mediator from also being an arbiter in the same case.

Mediators don't make decisions. They are referees and guides to help the parties make the decisions and reach a settlement. If one party is providing false information, they are in effect only providing that information to the other party. The mediator does not evaluate the evidence, and does not make decisions.

If the mediator is acting as an arbiter, and the rules actually allow this (very rare), then the situation would be treated as an arbitration. And an arbiter has an obligation to ensure that the evidence being presented is truthful and accurate.