The strata manager is employed by the Owners Corporation and answerable to the Executive Committee and my understanding is that generally speaking there is no confidentiality within those bodies. That means, for instance, if an owner is in a legal dispute with the OC or EC, they can demand to see all correspondence.
However, good strata managers will use their discretion as much as they are able and will treat some issues in confidence. However, there may come a point where they are privy to information that they simply can't keep to themselves and still do their jobs properly, especially if issues of professional liability are involved.
So I would err on the side of caution and assume there is no confidentiality in correspondence about the strata plan, regardless of what you put on the email. The strata manager's legal responsibility is to service the Owners Corporation, not individual owners.
You can ask them for discretion but I don't think you have any legal comeback if they pass the information on to the executive committee.
Perhaops one of our strata manager mebers can expand on that.
The opinions offered in these Forum posts and replies are not intended to be taken as legal advice. Readers with serious issues should consult experienced strata lawyers.