500
With a runner at third and one out, a balk is called while the pitch is delivered. The batter bunts a fair ball that is fielded close to third and the runner remains at the base. The throw to first trickles past the first baseman and the batter runner heads towards second then stops, goes back to first and is tagged out.
What is the balk is enforced, the run scores and the batter runner is left at first.