This week’s ruling by the Ninth Circuit Court of Appeals on attorney-client privilege holds at least one key lesson for general counsel: If you are contemplating an internal investigation, you might want to document that corporate employees being interviewed understand that the company owns the privilege, not them, and can waive it.

The court spelled out the theme perfectly in the opening lines of its opinion: “We here explore the treacherous path which corporate counsel must tread under the attorney-client privilege when conducting an internal investigation to advise a publicly traded company on its financial disclosure obligations.”