M'yeah - The problem as I see it is that it becomes towns problem if there's going to be policy lynches or vigilante shots used on these people, and that it actually benefits scum who can just ignore them and wait for town to potentially kill off their own numbers. That in itself ruins the entire balance of the game.
The simple solution to this is for everyone to just stop casting placeholder votes on themselves and step up their game instead - If you won't be around and online near the voting deadline, at least cast your vote on whom you find the most suspicious. That's what I do.