The reason I voted NO is mainly because there is a setting/plot/whatever you wanna call it which is basically that we are all members of a town and we're trying to figure out the bad guys.
How then, does it make sense that someone can come in anonymously and affect the game? If this were possible, it should have been laid out in the rules.
The only problem isn't the "unfair advantage," it is the fact that it completely changes suspicions and the way we all play the game.
Bad form
P.S. If this is something that is part of the normal game, it should be something that is controlled by the narrator. Leaving a suspicious note that is found by everyone in the village would make sense, but again, this type of gameplay should be well known before the game begins.
How then, does it make sense that someone can come in anonymously and affect the game? If this were possible, it should have been laid out in the rules.
The only problem isn't the "unfair advantage," it is the fact that it completely changes suspicions and the way we all play the game.
Bad form
P.S. If this is something that is part of the normal game, it should be something that is controlled by the narrator. Leaving a suspicious note that is found by everyone in the village would make sense, but again, this type of gameplay should be well known before the game begins.