Transmitting such sensitive information via fax gives rise not only to the possibility that an adverse party will inadvertently gain access to the information but also that it may simply cause embarrassment to the client if a friend or co-worker inadvertently sees such information on a widely accessible fax machine. In light of this admonition, it is good practice to discuss the use of fax machines with your clients at an initial stage of representation. If the client is agreeable to the use of facsimile transmission for communications directed to him or her, the attorney must nonetheless be cautious if any material to be transmitted contains sensitive information. Call the client in advance of sending any such information to be sure that only the client will have access to it. In such cases, the issue arises as to whether such information retains its privileged status or whether the privilege has been waived as a result of the disclosure, albeit unintended.
Jurisdictions are mixed as to whether waiver has occurred.
Many attorneys have faced the ethical dilemma of what to do about confidential client information about an adverse party received inadvertently. A misaddressed envelope or misdirected fax with sensitive information about an adverse party has the annoying proclivity to cause ethical heartburn for the attorney who receives it and may benefit by it if used to advance his or her client's interests. As with all thorny issues, there is no one rule on how to handle this dilemma. However, a California state court has ruled that the lawyer-client privilege shields against deliberate intrusion, and not inadvertent disclosure. The Court vacated sanctions which had been imposed upon a law firm for failure to timely disclose innocent receipt of privileged communications.