It might be worth editing more instructions to submitters into this post. Along the lines of 'If you notice that the previous thread has expired, feel free to post the next one. It should run monday-sunday, and it should include the open_thread tag so that it gets picked up on the sidebar'.
You know the drill - If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
And, while this is an accidental exception, future open threads should start on Mondays until further notice.