It seems the last signer (or organizer) has the advantage of choosing
when the transaction takes place and the money is withdrawn from all others' wallets. What if this person waits one week, one month or one year? Well, you could just send the money to some other wallet I guess so that it's impossible for the organizer to complete the transaction a long time later if you wish to "cancel" the transaction.
If they never sign it, the transaction is never valid and money never moves.
My point is, how do you know if they
never sign it? They might just be very, very slow