If everything else went to zero, sure. But if everything else went to absolute zero, there are bigger problems than running out of reserves in Cushings, right? Technically if all other input was completely unavailable, I imagine it would have to be some root cause which would probably make the oil in these tanks unmovable as well.
I've read the strategic reserves are more a political play, and a impressive engineering feat, but actually drawing them down doesn't provide nearly the economic value versus just the fact we have them.
If you think Cushing storage of 3 days is massive, you will be shocked with Strategic Petroleum Reserve maintained by US govt, that covers a large swath underground below Texas and Louisiana states, and only holds about 30 days of consumption.
Actually, Cushing storage is not that much. Unlike SPR, it is mostly short term storage in between transit. Cushing is a transfer point between different pipelines that connect at Cushing which also later became a delivery point for oil and gas futures traded in futures market.
I've read the strategic reserves are more a political play, and a impressive engineering feat, but actually drawing them down doesn't provide nearly the economic value versus just the fact we have them.