Is the media event available as a live stream? Or is it something that media types are just attending and reporting on afterward?
I don't believe it's being streamed.
There was a travel agent event earlier -- I was expecting summer discounts to be announced, but (according to reports) it ended up being nothing but a rehash of known information.
The 4:30 event may be nothing more than promotion of Disneyland's re-opening. No indication from any source I've seen as to whether anything "big" is coming out of the event.
Plenty of rumors are flying about night time entertainment right now. But even those rumors don't quite suggest that any announcement is imminent.