(Since my role will be revealed at death, there isn't much point in not posting the (long) "cheat sheet" for both a town BV and the town if it's a scum BV: )
I'm the goddamn Batman Neighborly Voter. This means, that whoever the BV is, will, at day's end, have the person they voted for at the end (it only counts who you voted for last; unvoting and not voting again means nobody will get the message (important for town to know, me thinks)) receive a message about the BV's alignment. If the BV does things correctly (i.e. not do like me) as town, they can become a confirmed townie (without PMs fortunately for the game's resistance to breaking; unfortunately for town). If the scum is is the BV, then they'll either have to find a legitimate reason to vote the person obviously being lynched without appearing to bandwagon so that nobody gets the message that they're scum, unvote, or vote only for their scumbuddies.
Recap with NEW AND EXCITING SPECIAL EDITION content: (1) As town, BV has possibility of becoming CT, but this should only be known by townies (if the BV plays his cards right/is lucky). This person should follow the following: [a] vote for the person being lynched without drawing attention [ b] unvote barely before day's out if the person he actually thinks is scum is not being lynched and probably do the last: [c] switch votes to someone you actually think is town before the end of the day (no hidden messages there!) so you're sure a Mafioso will not get the alignment message and off you that night, making sure you don't get the chance to tell fellow townies about your alignment (2) as scum, BV will always need to do one of the following: [a] bandwagon without drawing attention [b ] unvote at day's end [c] vote for his scumbuddies as it doesn't matter if they get the message. The last is the least detectable until said scumbuddies die and flip. The last can also be used to find remaining scum if scum BV dies first.
C for townie is the most useful thing the NV can do. Hell, I'd say not doing it is anti-town. And C is probably the easiest to hide from the opposition without taking too much notice, whether townie BV or scum.
Basically for town, just look for those 3 patterns this day forward: unvoting without revoting, voting for scum when said scum aren't being lynched, and voting for people who are lynched. These patterns will likely take at least 2 days to establish (as in, being useful Day 4 and onwards).
After typing all this out, it sounds less useful than I thought at first. But it's better than giving a Double Voter, Vote Delayer, Vote Seer, or Secret Voter to a scum BV. This is mainly useful if the BV is scum and/or is not EK. And I'm almost guaranteed to be Night killed sometime anyway, as I doubt town would lynch me under normal conditions now. But I doubt that we could have focused on someone else anyway.
And BV cannot reveal themselves whether they're town or scum, so don't do a massclaim unless the BV is already dead. Otherwise it's kind of useful.
WAIT A SECOND
POSSIBLY USEFUL THOUGHT INCOMING
Web, what would happen to the Backup Voter if 2 people are lynched? Does he gain both powers? Does he gain neither power? Does he gain the power of the first person to gather the required amount of votes?
NO WAIT THAT'S NOT USEFUL because then we'd probably end up taking away almost a third of the game; lynch me, I'm a townie; lynch someone else, probably a townie; random townie is NKed by Mafia.
Oh God. What have I done. This was a terrible idea. I should have just defended myself. Instead I guaranteed I would die, whether by lynch or NK. And by NK means my role goes to complete waste. Oh well. Too late to turn back now. I just hope BV's scum. =/
I suppose it's better than possibly giving scum a more useful role for them. Like Secret Voter when their fellow scum already has the Vote Seer role (and thus requires more effort and several days to be found out). Or Ice Cream Voter when their fellow scum is the Vote Seer, so they can use their special information to make the Double Voter (as town) a vanilla townie every single day.
If the BV is town (and is not EK and therefore not paying attention), they are probably banging their head against the wall right now.
Oh well. I'm off.