I hate that too, when people leave the mansion game just because they're losing or whatever. Don't they realize that you get credits for each ghost you catch even if you lose the game? Maybe they should charge people credits to play like the pirates game.
I like being on teams where it's me against two or three other people. I always get a lot more ghosts than usual, even if I don't win I more than make up for the forty credits.
I agree with the part where they should put in a charge like the Pirates game,
but I disagree with your second statement.
While it's nice for you that you can get more ghosts playing alone against
two or three other players, it's not fair to the others if you do this without
asking if it's ok with them. The player who plays solo has the best advantage
to get the most ghosts (and credits), while the other team has to share.
The other drawback is that if the solo player crashes, the other team is
stuck without a competitor.
Whenever I see a player starting a new game, and I see 'Join purple only',
I will not join the game. I prefer even teams unless I'm playing with friends
and it's ok with the rest of us, with only a 1-player disadvantage.
My particular peeves in Mansion are not only those who quit, but the
players who start a game
without reading the instructions and have never
played before. I wonder, why start a game if you don't know how to
play?

I don't mind new players who struggle catching ghosts,
if it's apparent to me that they
know which button triggers the vacuum!
More often then not, I tell them to "click the control key to clean
ghosts" and also "please click the instructions button in the game lobby
when the game is over" .