I keep an extensive banlist of people who quit early. Many times when I boot people, they will repeatedly rejoin the lobby after I boot them until it eventually crashes. (I am aware of the strategy of closing open slots until they go away, but often it takes a long time for them to go away and the other players in the lobby aren't that patient.) Some might say that my game crashes just because it can't handle the spam-joining, but I suspect that some people might have a way to force it to crash. This is because it has crashed before when the banned player rejoined only one or two times. Could they be placing some sort of folder in the game files that makes it crash for other players?