This frank exchange can be achieved only if the participants know that what is said in the mediation will not be used to their detriment through later court proceedings and other adjudicatory processes ... Such party-candor justifications for mediation confidentiality resemble those supporting other communications privileges, such as the attorney-client privilege, the doctor-patient privilege and various other counselling privileges
(a) Except as otherwise provided in Section 6, a mediation communication is privileged as provided in subsection (b) and is not subject to discovery or admissible in evidence in a proceeding unless waived or precluded as provided by Section 5.
(b) In a proceeding, the following privileges apply:
A mediation party may refuse to disclose, and may prevent any other person from disclosing, a mediation communication.
A mediator may refuse to disclose a mediation communication, and may prevent any other person from disclosing a mediation communication of the mediator.
A nonparty participant may refuse to disclose, and may prevent any other person from disclosing, a mediation communication of the nonparty participant.
(c) Evidence or information that is otherwise admissible or subject to discovery does not become inadmissible or protected from discovery solely by reason of its disclosure or use in a mediation.
"Section 4 sets forth the evidentiary privilege, which provides that disclosure of mediation communications generally cannot be compelled in designated proceedings or discovery and results in the exclusion of these communications from evidence and from discovery if requested by any party or, for certain communications, by a mediator or non-party participant as well [...]"