Well, there are two significant dangers:
1.) Innocent townies will honestly claim their names and, after much wiki and google searching, we will kill them because their characters’ are ambiguous on the show.
2.) The cop will have a very cop-ish name or the doctor will be, say, a doctor, and the mafia will know to kill them.
2 could be a very serious concern, and sadly the people most in a position to know just how serious are required to be very quiet about it. 1…I’m not sure whether that would be an issue.
Weighed against this is the benefit:
1.) The mafia will, likely, need to choose false names (assuming that names reflect natures). These names may duplicate town names, thus revealing them/forcing conflicts.
This comes down to the size of the cast. If this were, say, star trek themed, I’d say that the potential benefit is non-existent; there are too many characters. How big is the cast of Lost? If the mafia do a search for minor/single-appearance/only-true-fans know-their-names characters, how long a list is it? This game currently contains 12-14 real town names (I’d guess). If the total cast were 20 this would be a slam dunk. If the total cast is closer to 40? Different story.