Since I am not an insider, I wouldn't have any idea what their notice would be. However, if I were to guess, I would say they knew shortly after the BOD decided the course of action.
I would imagine the reason they did the blackout was to ensure people weren't selling. I don't know for sure, but it is possible that this might have been a concern in the past. It is my hope that they haven't done this solely to prevent insiders from playing but rather that there is something good going on.