SMRT has been wise in allowing charters only during off-peak hours. The practice makes sense for commuters too. Would you rather have the schools (neighbourhood schools and ACS(I)) involved send their children en masse via the MRT without any prior warning to SMRT? When the schools decide to make their kids all queue up at the MRT station, they are members of the public you know. They have every right to take the train. In this scenario, SMRT cannot plan for the suddenly large influx of passengers. Instead of sending in more trains, to relieve the high volume, SMRT would have to make public commuters wait 5 times longer to board their trains.