I'm convinced Greywing is the last scum. He seems to have flown over everyone's radar because of the whole Om outing himself situation, where he claimed to be masons with PG. This shouldn't clear him.
Ok, so let's assume you're Greywing and you're scum. You see PG about to get lynched; you're uncertain of his alignment, but he has just claimed mason. Now, you know PG is town, but are unsure of what to make of it; hammering would be too obvious on a claimed mason, and lurking/not commenting would raise some alarm bells. What do you do? You claim to back him up as a mason. When PG flips town (be it mason or VT) you instantly gain some towncred for trying to save him. If people believe your claim, the masons will obviously react differently and be more confused about whether or not you're masons/scum.
The purpose of such a gambit would be threefold:
1. Try to get a mason counterclaim, thus getting PG mislynched (as presumably he's a scum associate of yours) and giving the scum info on the mason flip (from the mason counterclaim). The advantage to scum is obvious.
2. Blatant reaction testing. Even if no one flips, scum can narrow the pool of candidates to those who seem to be obviously confused by the mason backing up claim. Advantage: scum.
3. Gain massive towncred. When PG flips town, it appears as a town gambit to save a town player. You can claim VT who tried to draw scum shots.
Further cementing my belief that Greywing is scum lies precisely in what should have happened when he claimed; the scum SHOULD have tried to shoot him and failed. Now, admittedly, there wasn't much time between his claim and Om's counterclaim; BUT in that small timeframe, two CONFIRMED scum posted, without taking the shot at either Grey or PG (Whiskers and seilkops). Why wouldn't they take the shot on two masons? Sure, no flip had occurred, but the apparent attempt to save a mason partner by Greywing should have warranted an attempt (and anyone suggesting scum are just playing overly cautious, clearly haven't seen the totally unprompted shot by Whiskers that failed or the shot by seilkops before he'd even gotten to L-1). Despite the fact that two confirmed scum had seen this play out, no shots were taken.
Why were no shots taken? Because they knew Greywing was scum with them. Whiskers tries to subtly influence the town to go along with Greywing's gambit, by proposing (in post #276) that:
"Claiming masons is an incredibly bad move for scum. If one of you flips scum, the other one will be lynched immediately. I don't think PG is scum, regardless."
Whiskers is hedging his bets. If Greywing somehow gets lynched or flips on a missed shot, PG is then lined up to be mislynched to offset the scum loss. If PG flips, it is presumably going to clear Greywing (which, up until this point, most people seemed to have agreed with). Notice Greywing himself hasn't voted for a scum player all game, defended Sala as a town player, and attacked DJD, who is now my strongest townread. Furthermore, although Sala very rarely references Greywing personally, he began to attack me only AFTER I attacked Greywing. Seilkops also adds to the associative links in Post #278 by helping establish a connection between PG and Grey, which again is an advantage by either PG flipping town and giving Greywing towncred, or Greywing flipping scum and making PG an easy mislynch. Seilkops even tries to coach Greywing into not doing this again. In Post #352, who is Seil's biggest townread? Greywing.
In conclusion, Greywing's mason claim with PG was meant to both gain him towncred and draw out masons. This is exactly what he accomplished. The only flaw in his plan was in the absence of a shot against either him or PG, despite two scum who obviously fired rather indiscriminately posting before a counterclaim. Greywing wasn't shot at because he was scum. This is backed up by the early interplay between him and Sala, refinement and support of his plan by Whiskers, and coaching by seilkops.
Vote: Greywing