A good point and we have to think of ...the poor player who's enemy walkover is not his fault. This is like an indirect penalty which is unfair to him. At this stage is a knockout not a round robin system.
Mr Hoang Dinh Hong of Viet Nam once taught me that in CHIchess look for the simplest, direct way to win. Based on the same logic, it probably is a better idea to keep the rules simple yet able to handle contingencies without unnecessary penalizing outside the player's control.
---kurubear
piggy888 hav a good point, how can we have a walkover in the knockout stage?