In the SVB situation, most of the losses are borne by the bank, investors of the bank, and the general public (in the sense that it caused financial instability across the nation). It's not a prisoner's dilemma because the downside to not cooperating is mainly borne by other people. The VCs and the startups who decided to "defect" are fine.
I'm personally unable to understand the anger here and finger pointing here, the bank was obviously in a bad shape due to their assets being underwater, why would bank clients have a moral responsibility to continue depositing in a bad and failing bank?
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And btw, the fact that parties could communicate with each other doesn't really change the game much. And nobody in their right mind would sign an agreement to keep assets in a bank or face penalties just because of some moral obligation to protect shareholders of a bank that made risky bets. That's just nuts IMHO. Anyone is free to create a time deposit if that's what they want to do.