I've had this happen to me multiple times where I'll join a 6 player game, confirm, but then when the game starts it's only 4-5 players.
I just wasted 45 minutes playing a 4 player game that was supposed to be 6. Turns out 2 of the four "players" were actually a cheater using multiple accounts.
If I sign up for a 6 player contest I do not want to play a 4 player contest, especially when the person running the game is usuing 2 of the 4 accounts.
The person cheating was Little Fortune 19 and the other account was CoreTV, watch out for "them".