Here's something I was thinking about for future games:
OK every vote for a poster is tallied at the bottom in the event of a tie in votes. However some of those votes will come from players who are actually MAFIA.
I think it might be good, when and if a player is revealed to be mafia, to have any votes they've cast that contribute to another posters vote tally voided.
It wouldn't help any unfortunate citizens who'd been band wagoned to death but it'd be useful for survivors in subsequent rounds.