I think Jeff has it exactly right.
If they are going to requisition food supplies they need truckloads, trainloads, shiploads. Not a few cases of tinned beans here and there.
It would be the warehouses, feedlots and grain silos that would get used.
In North America the biggest problems would be setting up the soup kitchens and the transportation instead of getting enough food to feed people.
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I saw a band of spiky haired mutants once, not quite bluegrass music, but not far off.