It’s a good wincon for scum to hide behind it.
Eh, but it's not really, though. Ultra will, at some point, be removed from the game. Naturally there will have to be something happening with Blue there. Either he'd be removed, or his role would change, but we'd probably see some form of confirmation there. If nothing happens, and Blue still comes up as Guilty, and there is otherwise no real update here, then he essentially has nowhere to go. This is doubly true because the other remaining Wardens will be resolved in a certain way, so if Blue isn't treated the same way then he's also caught there. For him to be lying about this, he'd have to have made several assumptions about the setup to secure a "I am not Town" claim that will last until D4 or maybe D5.
If I were you, I'd be more focused on the other players in that list, whom you should have a very strong inkling towards being Scum, if you are in fact Town.
Brann's Beard is humorous.