If a running bowl displaces a jack after hitting a non-toucher, what should happen?

When a running bowl displaces the jack after hitting a non-toucher, the correct procedure is that the opponent should replace the jack. In lawn bowls, the integrity of the position of the jack is crucial for the continuity of the game. When a jack is moved due to interference caused by a bowl hitting a non-toucher, it is the responsibility of the opponent to restore the jack to its original position. This ensures that the game rules are upheld and that the play remains fair, maintaining the intended setup of the playing area.

In this context, the other options are less valid: the jack cannot remain where it is because it has been displaced; the non-toucher, which is an inactive bowl and not part of the scoring, does not influence the position of the jack directly; and requiring the player to play their next bowl from the same position does not apply in this scenario where the jack's position has been altered. Therefore, having the opponent replace the jack is the appropriate action to take following this occurrence.