In business communication of every kind, voice, text, emails, paper sticky-notes, doesn't matter. Assume someone is sharing your information with someone that you don't know is sharing it. Communicate as if you have an audience at all times. Also, I am not a lawyer, but the error rates are too high for anything transcribed to stand up in court with a good lawyer, unless corroborated by human witnesses.
you are talking management level intelligence to a very Individual Contributor crowd. People will nuke every opportunity presented to them in their life in defense of NDAs that don't matter - better called Not Doing Anythings.
