I don't agree that that's an obvious risk.
A big reason I deposited with Patrick is because he is assuming the risk of loans going bad. If I knew that his guaranteed deposits really meant "guaranteed unless loans go bad", then I never would have deposited with Patrick. If I wanted to assume the risk of loss (and thus potentially higher profit), I could have made loans to other people myself.
I think you're misunderstanding my argument. It isn't about the foreseeable risk that loans would go bad. I agree that Patrick assumed that risk.
You're saying I couldn't have foreseen the possibility of Patrick's loans going bad, and thus Patrick shouldn't have to pay me back. That's false. I did expect there was a possibility Patrick's loans could go bad. That's the whole point of depositing with Patrick: he guarantees his deposits against that scenario.
I agree. I'm talking about the risk that the loans were correlated, that is, that a common event would make a significant number of the loans go bad at the same time. If you have some evidence that you and other depositors considered that specific risk or that this risk was allocated to Patrick, I'd like to see it. All the evidence I've seen suggests that both Patrick and his depositors (at least those who spoke on the issue) either denied that this risk existed or never considered it.
By the way, this was the same type of missed risk that resulted in the mortgage collapse. People who thought they were "diversified" didn't realize that a significant fraction of their assets were vulnerable to a drastic drop in the housing market because they were all ultimately tied to residential mortgages. It always seems obvious in hindsight.