This is an example of a level of polish that should be in the game but just isn't there. Great move by EA to allow clubs to fill open spots with drop ins. Not being sarcastic there, it was a smart improvement. It really has been beneficial for club teams short a guy or individuals who want to drop into something better than the chaos of a full drop in match up.
That said, it falls short that they implemented this into a ranked mode without appropriate guard rails/tools. Clubs (maybe the captain) should absolutely be able to immediately kick a drop in player from a game or locker room if they deem that player is trolling or throwing.