Hi bird, In normal open tournaments, the loser always get eliminated. If someone withdraws, the opponent gets a walkover. No score needed. Just add w/o on the record for the winning player/s. However, in group matches, where number of sets and points per set may be required for countback, the default score is the duck (15-0, 15-0). Remember, this is only needed for group matches where the loser is not eliminated immediately, like in Thomas/Uber/Sudirman Cups.