On the ATP level... if you can't play, you still get your prize money twice in the year. Maybe the grand slams should adopt some of that, then maybe we would eliminate half of the players (who turn up injured), a player should not go on court if he knows he could not finish. The question is, did they truly believe they were going to finish? If they did, I think it's okay that they walk on court. Otherwise, I feel they should give up the spot.