It seems it wouldnt be hard to implement an approval of some sort for as bluedart said a certain percentage or maybe even a set amount.
If someone tries to withdraw say more than 50million then it has to be approved by another member of government or something. But there would also need to be a way to prevent multiple smaller transactions.
All in all I think alliances need to be more trusting in who they choose to have access. It sucks regardless but it adds another level to this game.