Moreover, it's fluff. There is nothing substantive about an announcement of an announcement.
Normally I would agree (and I hate these announce-that-they-will-announce things in general) but in this case, there's a stream that a lot of people here would probably enjoy watching live, so it's nice to tell them ahead of time.
It still has almost six hours to go, why post this now? There's a good chance this will be gone from the front page by the time the event happens.
'Live' meaning 6 hours later than the time this was submitted ....