I have wanted to propose something along these lines, but a comment by rjzii stated it very well:
@GeorgeStocker In all fairness, an official SE post should just be locked from the beginning as a matter of policy. I'm not sure if the back-end supports locking the question and still allowing responses to be made.
During the time that the announcement in question was locked, it was not possible to add answers to the question, comment on it, or vote on it, even though the purpose of the lock was apparently just to protect the exact content/text of the question (as it was an official announcement and not a problem statement with scope for community improvement), rather than to prevent answers, voting, etc.
Let's create a new lock, the Official Announcement Lock (TM). This lock will prevent edits to the question, and possibly closure, but will allow all other actions - commenting, answering, adding bounties, and voting up or down. The text might look like this:
Locked as an official announcement. This is an official announcement from Stack Exchange and may not be edited by the community. If you wish to provide constructive feedback on or respond to this post, you may vote on it or post an answer. If you believe that this post needs an edit, flag the question or raise a new question on Meta.
