Proven stuff in mafia: Stuff that acts with other people's roles in ways they can confirm. I can pretty much prove my role tonight, but that's doesn't prove alignment. Anyway.
Did you not see all the hemming and hawing I put into the neighborhood QT when I was scum neighborizer in Mirai Nikki? And as for the Rocks Fall thing, like I said, I'm wary that he didn't bring it up earlier when there were people who could do stuff about it, especially since at that point there was no downside to outing it.