I had a brainstorm while scooping the litter box.
Reading DDL's role, I see this:
[Rainbow List]: Once in the game, Sockface can send the host a rainbow list, ranking all the players from most civ to most bad. The 1/3 of the players leaning most bad will be roleblocked for the night, and the 1/3 leaning most civ will be protected from night kills.
So, that one night when no police arrests went through and junk, and we were convinced they had sussed out the Dons... perhaps that isn't true. Perhaps this power was in play? So maybe they don't know the Dons at all.
I had a point to that, but since I didn't come straight here to type (due to kitty litter hands) I can't remember what point I was trying to make. Anyway, there's at least half of a thought. Maybe the rest will come back to me.