[PeterisP]

I don't really see what's the crash mechanism there.

From the lender side, repo financing is collateralized so if someone can't pay, then the lender doesn't care because they've got the collateral bonds already; it's not ideal, but it's not a disaster.

From the borrower side, if someone really needs short-term liquidity and would have usually used repos but can't get any right now, then they do have available bonds that they've used as collateral for that repo, so if they really need cash then they can sell the same bonds instead of borrowing against them. Again, that's not ideal and they'll probably lose some money on an urgent sale, and their plans to earn some profit on that borrowed money won't materialize, but that shouldn't trigger a crash that would affect the whole system.