It is not announced. (Very few of Oracle Loramelian Ueda's works are, after all.)

It is likely not even known in advance. Secrecy is the name of the game, for something like this.
Pieces move with little coordination or communication, independent movements of information carefully siloed.
Strings connecting only at one central knot.

When the count of Midpoint's bail money exceeds two million coins, the order quietly goes out.

Objective: Ambush the Midpoint bail money transfer before the bail can be delivered to the Archmage's Association. 

Prevent the Chairman's release and take back some of what has been taken in turn.