(a) A practitioner shall always treat adverse witnesses and other litigants with fairness and due consideration. He should never minister to the prejudice of a client in a trial or conduct in a cause. The client has no right to demand that the practitioner representing him abuse the opposing party or indulge in offensive personal attacks.

(b) A practitioner shall not attempt to obstruct Board investigations or corruptly to influence witnesses and potential witnesses during an investigation.

(c) In conducting a case it is improper for a practitioner to allude to the personal history or the personal peculiarities or idiosyncracies of practitioners on the other side, or otherwise engage in personal abuse of other practitioners.