We've all been there. You're in a lobby, and theres only 1 space left. You just want someone to join so you can get started. Where oh where will your saviour come from? Will it be one of the 18 spectators? Probably not, because they're just sitting there waiting for one specific player to leave, instead of just joining an empty spot in another lobby.
Perhapse if you could Queue for a spot, then we would be able to disern the actuall spectators, from the people just waiting around.