Saying that an all-vanilla game is a possibility tacitly suggests that you are a vanilla, regardless of the truth of the situation. This is a bad idea, for a couple of reasons that I outlined in a previous post. I think it was probably a good thing that the idea was nipped in the bud because I think operating under the assumption that there are no roles would have made it very tricky for the roles to operate, and would have given the scum a lot of opportunities to push for a lynch of the roles once they claimed. After all, why should we believe them, they lied before and said that they were vanilla? It's a sticky situation that would be best avoided.