spectator option

if someone joined a room and pressed start, this would happen
1. player will be assaigned to a team and start playing the game(normaly)
2. becoming a spectator instead of playing the actual game(least possibile)
Now why can't we have the option of being a spectator (or not) instead of being assaigned automatically?
this would be more convinient if someone wanted to watch a match and not play the game.