Now, can I suggest another type of spectator: The Watching Spectator. It's like checking the Spectator box before joining a game. You will then enter this server, but you cannot join the game in any way.
The trick is this: Let's say there are 4 players in a room for 5 people. You enter as this "Watching Spectator". The number of people in the room will still be counted as 4 as the server does not count in the watching spectator (they are counted separately). At least now, you don't have to take up the space in which other players want to have because they want to play, not to spectate.
Servers can disable Watching Spectators or put a limit to the number of watching spectators.
What do you think?