Jash, I saw this during the floods, as I was working as a checkout chick at the time. There was no "orderly fashion" to speak of, either. People stood six deep in front of a display of a particular item, while the person closest to the display took every item, leaving nothing for the people clamouring behind them who were obviously waiting to get some too. This caused much grumbling, but not as much as there would be if people knew how long it was going to take to re-stock.
I saw a father with little kids skipping along behind him, emerge from a Brumby's store with a scowl on his face and two 15kg bags of flour on his shoulder. He was positively furtive, looking around at people as if they were going to take his flour.
Curiously, the frozen foods were almost completely unaffected. No one was stocking up on them, presumably because they all thought the power would go out. Everything else went, including things that wouldn't really have come in handy in an emergency, but were just bought by people keen to stock up on SOMETHING, because most of the food was gone. The prices didn't go up, as it was a large chain, but the fish and chip shop's cigarettes were $50 for 25.
I had a couple of "refugees" for a couple of weeks, who weren't allowed to go home. Fortunately I was prepared. From my point of view, I couldn't work out why so many others didn't see the shelf-emptying coming. Sometimes people do see it coming, but this doesn't change the amount of money they have available for food in a given period. Logically, if you have not a bite of food in the house at all, and blame a flood that's been going on for two whole days, I don't see how that's anyone's fault but your own. On the other hand, that's not a very compassionate opinion. People don't expect the infrastructure that's always been there to suddenly vanish. Preparing that far ahead is beyond some people's capabilities.