Ok, this is a weird one that happened today (12U USA game). Batter hits a clean single to outfield, rounds first. Our player throws to first to get the runner, overthrows, and ball strikes a player from the other team that was "in the hole"; emerging from the dugout during the play to go to the on deck circle. Should this be "dead ball", runners return to last base occupied? Their player should not have entered the field of play until the dead ball, IMO. Umpires allowed BR to advance to second, which IMO was the wrong call. Thoughts?