A. Rules of privilege. Unless otherwise provided by statute, the Board need not observe the rules of evidence observed by courts,, but shall observe the rules of privilege recognized by law.B. Evidence. Evidence shall be admitted if it is the kind of evidence upon which reasonable persons are accustomed to rely in the conduct of serious affairs. The Board may exclude irrelevant or unduly repetitious evidence.C. Witnesses. All witnesses shall be sworn.D. Written evidence; exception. No sworn written statement shall be admitted unless the author is available for cross-examination except for good cause shown.01-020 C.M.R. ch. 3, r. 16