I would basically agree with this, and certainly this is the case in the more rural areas and towns that we have mostly seen on the videos.

I can't imagine normal Japanese swarming a supermarket and just carting away stuff right in front of TV cameras and scurrying away. Of course, every culture has its criminal element--even Japan--and they may cause some mischief. However, calamity can often bring out the best in even criminals.

If things ever got so desperate that the contents of some business were needed (and who knows, it might come to that), instead of going in and stealing it themselves, the people would most likely ask the owner or ask the authorities to ask the owner and the owner would likely just donate it all. If the owner couldn't be found, the supplies would be commandeered in some rational, orderly fashion. Probably not dissimilar to what you might see in many tightknit rural communities even in the US still.

Not that anyone has any guns in Japan, but you'll never see any need for merchants on rooftops waving shotguns to scare off looters or armed "neighborhood watches" and checkpoints like in the Cairo uprising.

That said, there can be a dark side to Japanese, too. I won't go into details since it's apparently not relevant in this situation AFAIK. I just bring it up so people realize that I'm not saying the Japanese are all just angels in human form.

Edit:
Here's a Washington Post article I just read called, "Amid catastrophe, Japan fights mayhem with order."

This description is very illustrative (remember this is IN the disaster area):