I did not know that. Does the game suffer in any way by becoming a 6 player game so late in the game?
Note: That also answers a question I had during our first game Saturday night about tile numbers. manual calls for selecting 4 regular tiles per player and 2 special tiles. We ran out of tiles rather quickly in a 6 player game and at first I thought I was missing tiles. After finding out there were supposed to be 26 tiles from the components list, I wondered why they hadn't made mention of that in the rules.
The rules do mention that with 5-6 players you won't have enough tiles.