I am pretty sure that is what the coaches are for, but I like hearing Jerry Jones talk so here is the quote via PFT.
“No. 1, I wanted to go down there and do what I could, look our guys in the eye, look at them, inspire them to overcome Romo not being out there and overcome what I thought was a critical time,” Jones said on KRLD, via the Dallas Morning News. “First of all, I’ve been down there hundreds of ball games. Everyone that follows it has certainly seen it, either criticized it or whatever or lived with it.”
He points out other members of management and owners are on the sidelines, which is correct, but they aren’t doing this to their coaches in the middle of the game.
It is Jerry Jones’ team and stadium, so he can do what he wants, but I doubt many people want him on the sidelines micromanaging.