The Vigilante is seeing exactly what we're seeing. He can't be any more sure about someone being scum than we are on deciding for lynch.
I'm still pondering probabilities.
It's 7/10 chance to get townie and only 3/10 chance to get scum. I prefer to have more townies than less. I advocate the N-L word on Day 1 when it makes sense. However, there's a 1/10 chance of hitting the Serial Killer which could save townies from dying in future nights. Unfortunately, the Serial Killer has 1-shot night kill immunity so it would take 2 nights to kill him. Maybe the Vigilante should save his bullets after all.
I'm going to respectfully disagree here. I think the Vigilante has a higher chance of hitting scum then us lynching. This is because he does not have to try to convince the town that someone is scum and try to get enough votes while the scum are defending that person. He can just choose one person to get rid of. I think that the town has a better chance with the Vigilante nightkilling someone. Hopefully the vig agrees and does what he thinks is best.