I have been puzzled by the same thing as Michael on this.

The only answer I can come up with is that the spare capacity has been calculated for the whole day and if lots of spectators try and get to an event during rush hour then this will cause the congestion that is clearly being planned for. In this context, it would make sense for commuters to make alternative arrangements - *if they can do so*. Otherwise, I see no reason why this should spoil our enjoyment of the games.