If you intend to influence your opposition (assuming that you ARE in opposition, which is debatable as you noted) do you remind them that you are reading their mail? If you are actually reading their mail that is? There are many communication techniques which are quite a bit more opaque to the NSA and other signals intelligence collection agencies than email or telephony. Human couriers to name one. More on sources and methods I’ll decline to elaborate on an open channel.
Oh yes, low tech craft defeats billions in tech eyes in the sky. In plain sight and conversation. Understand your point and non-elaboration.