When discussing confidentiality, the definition is essential. It would be incorrect to assume that emails sent among board members are confidential by default due to the recipient list. Square up that assumption with any common code of ethics and you'll find that "context matters." Emails amongst board members and their community manager are generally not privileged which stands in contrast to a privileged email between an attorney and a client.
Many of us have learned over the last 30 years of email that the Forward button is imminently convenient and that replies sometimes surprise us when additional recipients have been added. Emails are unlikely to be considered confidential by default unless they include confidential information. While WA State's wiretapping laws prohibit recording conversations without the consent of other parties, there are no blanket prohibitions against sharing the contents of an email with a third party.
What's actually confidential? WA State's WUCIOA statute defines the essence of confidential material in RCW 64.90.445(2)(b)(I - V)
There's no reason to be confused about what's confidential or caught off-guard when words you put in writing end up somewhere you may not have intended. Since confidentiality and ethics often intertwine, please visit our ethics page as well.