Yeah, when I read that I tend to think we're fine.
It would seem nearly impossible to have the ball attendant alter the balls, right? It would seem s/he is a paid member of the NFL. And there's zero chance this was done on the sideline. There's no way you could get all 11 footballs to such a precise, uniform number.
So the only way this happened is if something was done to the footballs during that incredibly small window of time after they've been given the ball attendant, but before the game starts. Do they have the footballs in the locker room at that stage? If so, then it's plausible (but still unlikely given that it would seem that the ball attendant is independent of the team). If they're provided to the ball attendant on the field I can't possibly see how we'll be found culpable.