As usual I look forward to your thoughts.
I'm sorry, but my belief is that posting over public networks, entitles you to the same level of security as if you were speaking in public. As such, you must assume that everything you do, is watched, if even just electronically.
If you don't like it, encrypt everything, that is the only way to be sure.
Then the issue becomes whether you have the right to avoid self-incrimination,
when you are ordered by authorities to reveal your encryption password. I think that issue is already heading for the US Supreme Court.