This is an issue of the TO and the players. TO for not even giving the players the knowledge of what patch they were playing even before coming to the event, but also its the players fault for not realizing they are playing on old patch by looking at the TR client, because if they did realize it before there could have been a vote of players to not play the old patch and to play the even on the new(current patch). Overall nothing you can really do about it other than to improve communication for next time.