Make them shoot it out. Show respect to the tournament format rather than your opponent's ability to pocket a hanger.
I also agree that giving someone the last ball(s) can be a shark. That is less of a factor in the final rack, however, when you are conceding the match rather than conceding a game.
I also agree that giving someone the last ball(s) can be a shark. That is less of a factor in the final rack, however, when you are conceding the match rather than conceding a game.