If the withdrawal is before the half-way stage of the event, the withdrawing pair is deemed to have never played, and all scores against that pair are cancelled (with sit-outs created just acting as "not played") (2.4.4).
To state 2.4.5:
If the withdrawal is after the half-way stage of the event, the withdrawing pair is generally awarded Ave- for all boards they don't play. In the case of a "genuine and acceptable reason," 2.4.4 could be applied instead (i.e. all scores being cancelled) to avoid an undue effect on the NGS - the probability of this being suitable is reduced as the session goes on.
Assuming that scores are not cancelled, all pairs that were due to play this pair (but were unable to) are awarded an Ave+.
Note that an Ave- may not always be suitable for a withdrawing pair - in a situation where the pair is leading with 1 round to play, for example, they cannot decide to leave at that stage to ensure they finish top (by virtue of guaranteeing 40% for each remaining board). In this case, a reduced score down to potentially 0% for those boards could be awarded.
Just for completeness: 2.4.4 and 2.4.5 do not apply if it is an all play all event. In that case it is 2.4.2.
Note though that An all-play-all event is one that is advertised as such in the Conditions of Contest. An event that is not so advertised is not treated as all-play-all just because the number of entrants makes it possible for all contestants to play each other.
So a normal club session is highly unlikely to be all-play-all.
Last night a player unfortunately suffered a panic attack on the penultimate round and couldn't play the second board or the last round. (They seemed to have recovered somewhat after the end of the session and the director to them home). Out of the generosity of my heart I awarded 60-50 (and yes! I know it should be only 60-40).
Comments
The answers you are seeking are in the White Book 2019 2.4.
The actual resolution depends on when they left.
To state 2.4.4:
If the withdrawal is before the half-way stage of the event, the withdrawing pair is deemed to have never played, and all scores against that pair are cancelled (with sit-outs created just acting as "not played") (2.4.4).
To state 2.4.5:
If the withdrawal is after the half-way stage of the event, the withdrawing pair is generally awarded Ave- for all boards they don't play. In the case of a "genuine and acceptable reason," 2.4.4 could be applied instead (i.e. all scores being cancelled) to avoid an undue effect on the NGS - the probability of this being suitable is reduced as the session goes on.
Assuming that scores are not cancelled, all pairs that were due to play this pair (but were unable to) are awarded an Ave+.
Note that an Ave- may not always be suitable for a withdrawing pair - in a situation where the pair is leading with 1 round to play, for example, they cannot decide to leave at that stage to ensure they finish top (by virtue of guaranteeing 40% for each remaining board). In this case, a reduced score down to potentially 0% for those boards could be awarded.
Just for completeness: 2.4.4 and 2.4.5 do not apply if it is an all play all event. In that case it is 2.4.2.
Note though that An all-play-all event is one that is advertised as such in the Conditions of Contest. An event that is not so advertised is not treated as all-play-all just because the number of entrants makes it possible for all contestants to play each other.
So a normal club session is highly unlikely to be all-play-all.
Last night a player unfortunately suffered a panic attack on the penultimate round and couldn't play the second board or the last round. (They seemed to have recovered somewhat after the end of the session and the director to them home). Out of the generosity of my heart I awarded 60-50 (and yes! I know it should be only 60-40).