The Bank without the benefit of a secure layer is trivially exploitable.
For example, with very little thinking, you should be able to completely control the bank by using eavesdropping+forgery. If anyone or any team at any point before the secure layer is in place can demo (on their own Playground Sandbox) how to do this, I will buy it as an exploit. To be clear, the exploit must show how, using eavesdropping of legitimate bank traffic, a forger can completely control the bank. If you have questions about this, ask me privately.
I’ll pay 10,000BP to the first teams that produce it for me and 5,000BP to everyone else. Teams that demo for me on the same day are presumed to have tied.