I've been in the hurricane center at a large retailer (last week, in fact). Aside from freezing prices at before-storm levels, no one who volunteers for the 24/7 emergency staffing is thinking about the dollars. Sales take care of themselves.
They're doing it because it feels good to help people.
And because rerouting truckloads of supplies effectively at 2 AM means someone in the affected area will be able get to their nearest store and get the things they need.
I'm not sure why the comments here are so !%^&ing jaded, but sometimes you do the right thing... simply because it's right.