(1) A privilege under RCW 7.07.030 may be waived in a record or orally during a proceeding if it is expressly waived by all parties to the mediation and:
(a) In the case of the privilege of a mediator, it is expressly waived by the mediator; and
(b) In the case of the privilege of a nonparty participant, it is expressly waived by the nonparty participant.
(2) A person that discloses or makes a representation about a mediation communication which prejudices another person in a proceeding is precluded from asserting a privilege under RCW 7.07.030, but only to the extent necessary for the person prejudiced to respond to the representation or disclosure.
(3) A person that intentionally uses a mediation to plan, attempt to commit, or commit a crime, or to conceal an ongoing crime or ongoing criminal activity is precluded from asserting a privilege under RCW 7.07.030.