If you write a TV Script and it gets accepted, do you actually go out to the TV filming Set?

For example, Eric Kripke, who writes and created Supernatural, he works on the set of Supernatural. He is also an executive producer, and occasionally directs an episode. Is he only on the set because he's an executive producer, or would he be on the set anyway as he writes it?

So, if you wrote a Televison script, would you be expected to be, or even allowed, on the set whilst filming?