Not really true, collateral is decided at the end of the day and not mid day.

You aren't liquidated immediately the moment your needs more liquidity.

We wait till the end of the day short of absolute emergencies.

I know Amaranth well being in Canada and Calgary specifically at the time:)

And for tradfi a typical hedge fund gets a call and is told to post more collateral and they make real efforts to allow the fund to post collateral. There is almost never an immediate liquidation as this tends to cause more trouble than it fixes, even on the CME or CBOE:)