Because I've been working from home for over a month and generally have the TV on in the background. And like clockwork the daily briefing has begun between 4 PM and 5 PM Central time, usually between 4:30 and 5. That's how I know that.
Why do you argue such mundane points.
To correct incorrect statements.
Lou Dobbs comes on at 5:00 Eastern and has an exact replay at 7:00 that is why you see the breefings at the later hour.