Turn off one's lights for "a chance to win prizes." It's Privations for Prizes!
Gee, maybe one of the prizes is one of those bitchin' little solar-powered book lights.
As for why the power company is "caught up in this" remember that they are regulated by the Public Utilities Commission. It's for the same reason that insurance companies initially "supported" health-care reform. If they don't play the game, or at least pretend to, there will be hell to pay at the hands of our "protectors" in the government.
Wouldn't it be better to have a "brown bag" day when all restaurants shut down? Surely the energy needed to keep all those ovens, grills and dish washing equipment working far exceeds the energy used for a few office lights. Think how much energy a cold ham sandwich would save!
Do you supposed the restaurant association is really interested in being "green" or is this perhaps cynical opportunism to increase business? Not that I blame them.