I think a staffer's power ends at their game. I don't think that there's a universal fits all policy when it comes to incorporating off site information/behavior into a decision on the game.
I would not expect as staff on a game to control what people play about in gdocs. They can transgressive fanfic RP it up to their heart's content.
To be honest, a third party tattling under most circumstances would have me eyeing that third party. The main exception I could think of is if a player had been sending unwelcome links or harassing them via other methods when blocked from doing so on game. I hope this isn't common but for awhile on a game I played I did have that happen to me when another player got my email from a group organizational site (not even a RP one) and then started sending me links to stories they'd written where their PC assaulted mine. When I tried to get help for this from staff I was told since this was off site they wouldn't do anything about it. So I would remove a player from my game if they had already been told to leave someone alone on the game, and might have abided it there but started harassing elsewhere. Is that fair, I suppose not, but just in my own preference since that's very abnormal behavior, I have no issues removing people like that.
But that is harassing ooc behavior. When it comes to just storytelling between consenting adults? I might decide that I do not want that RPed about in a public sense on my games or not to support it at all with staff attention or the like, but I don't really care what people do outside of it. Unless they MAKE it my problem via indiscretion or boundary pushing.