So, it's after 7pm EDT already. Too late for the world news. It can't be too late tonight as people don't want to receive a text at 3:30 in the morning. It'll be before the first joint appearance tomorrow.
My guess is that they're timing it so that Bob Costas will announce it to the 50+ million watching the Olympics tonight. I'm thinking ~8:15 when they're busy talking about how great kite flying in China is rather than when they start with the actual competition.