Wow, just noticed the Wal-Mart posts below on the day I see this story, something I've heard about for a couple years but now has been fulled studied. The opposite of corporate policies preventing employees from doing the right thing, it's what happens when a company empowers employees to act as they see fit, as the Wal-Mart CEO did on the morning of Aug. 29, 2005:

This extraordinary delegation of authority ... saved countless lives in the ensuing chaos. The results are recounted in a new paper on the disaster written by Steven Horwitz, an Austrian-school economist at St. Lawrence University in New York. While the Federal Emergency Management Agency fumbled about, doing almost as much to prevent essential supplies from reaching Louisiana and Mississippi as it could to facilitate it, Wal-Mart managers performed feats of heroism. In Kenner, La., an employee crashed a forklift through a warehouse door to get water for a nursing home. A Marrero, La., store served as a barracks for cops whose homes had been submerged. In Waveland, Miss., an assistant manager who could not reach her superiors had a bulldozer driven through the store to retrieve disaster necessities for community use, and broke into a locked pharmacy closet to obtain medicine for the local hospital.

Empowered, decentralized actors - people on the local level given the authority to act - and the resulting response was leagues ahead of what FEMA was doing. This isn't testimony to Wal-Mart per se, but to the power of local, community actors as being in the best position to respond to disaster - look how well they did it!
Of course these managers would do everything they could to help these people - it's their freakin' home town(s)! Contrast this urgency with the disinterest of a remote FEMA bureaucrat in Washington who's never been to Gulf Coast... is the resulting difference any surprise?
(Note: The article I linked to takes this to a certain anti-federalization level, which you may or may not agree with. Personally, I'm always shocked at how many people who railed against FEMA in the case of Katrina support the same disinterested and distant federal government in rebuilding the Gulf Coast, and many other projects of this nature.)