When I lived in Santa Cruz, we had a day-long internet outage due to a fiber-optic cable being cut, which led to most shops not taking CCs, despite there being no trouble with the power. A few mom-and-pop shops did good business by essentially agreeing to take IOUs; they wrote down CC #s on paper and manually ran them later, although afaik that's contrary to most CC companies' policy: http://www.mercurynews.com/centralcoast/ci_12115324