I agree that we’re a bit of an edge case, feature-wise, but we’re definitely mainstream, behavior-wise.
I would love to know that our users would understand - and always remember - that they are logged in with one account vs another. But absent-mindedness is deeply ingrained. Typing into the wrong chat window, texting the wrong person, replying to all, or forgetting which account you’re logged into, are fairly common occurrences.
Policies are great, but they don’t fix human behavior.
I am currently looking at creating a custom trust level group, or equivalent functionality, which would not allow posting. A more open-ended approach would be to create a trust level group with admin-definable or admin-settable custom privileges.