Nope only requirement for this event is to reach Year 1 Chapter 6. And if you play when the event is active you are automatically included in the event. Just pray that no one from your group of 25 people report another member.
Depends, I had FMs where:
1)people had 1 million points
2)Another FM where several people were removed from the event.
And to this day, y7 I am still not banned.
Just don't collect the boxes/have abnormal amount of points and you'll be fine. The ones where, I THINK, You truly can't do anything Is the costellation event, in specific, the party where you contribute points for common rewards and the event where you have to contribute house points with other players.
Not having absurd stuff like 9 million Energy/gems and High stats per the relative year Is also a good deterrent.