Yeah, the whole idea of the mafia neighborhood was to give the mafia a chance to make "plays" i.e. set it up to perhaps bus one of their team members, or recruit villagers to confuse them etc. Basically, it could've been used a lot of ways to disguise themselves. On the other hand, it could also be entirely ignored, which I don't think is a terrible idea either. I put in the neighborhood checker to guard against that, in the sense that I felt that the checker would basically become an inspector - it wouldn't look very good to be found out as part of a neighborhood that wasn't really well known about (which the others seemed like they were). Nevertheless, UTO died before he could share that information, which was unfortunate as otherwise, I think that info might've shaken up the game a lot.