N/S at table 14, started by sitting out boards 25-26 in a normal web movement. They played 23-24 against pair 13 in round 2, but for round 3, took the lowest numbered boards from their stack, 9-10, to play against pair 12. This was not discovered until they passed the boards to table 13 at the start of round 4. As I was playing, I didn't have a lot of time to come up with a solution, so I gave the pairs that should've played 9-10 vs these two pairs Ave+, and these two pairs Ave-. First, should I hold E-W as responsible as N/S? I suspect not. Second, when I gave the non-offenders Ave+, I let the N/S play boards the E/W had played (for fun), rather than giving them a second sit out. I hope this isn't a repeating problem, but how should I have handled this? Will Engel Rockford, IL