Because all together, it can make a lot of time ( A new player must be found/matchmaking and the new player has to arrive/load the map). It could be kind of a incitement to stay (...) and be more fair for the unstaffed team. Just unfunny to arrive when every body is cracking his super, or you have to wait the end of the party to maybe have one. AND when we join a game in progress, could we at least know during the loading screen which map and mod ? Sometimes, the landing is brutal (saving private Ryan - the Normandy landing scene brutal...) ;