In looking at the lightsout.com.hk site, I see their list of supporters is WWF, Friends of the Earth, Greenpeace, Greenpower, Green student council, etc. No mention of Ogilvy.
I agree that companies usually have motivations other than altruism when they sponsor events. But I disagree that this sponsorship in any way invalidates the event. Ogilvy, if they are in fact a sponsor, are likely looking for good PR, and they are right to get good PR when they can find it. Wouldn't you rather they get their PR from sponsoring environmental events instead of hostile takeovers of sympathetic companies or false accounting practices? Who cares if they aren't in it only for the good of the environment? I certainly don't feel "manipulated" in getting the chance to express my dislike of and powerlessness over the HK air pollution along with other like-minded residents.
Another point people seem to raise in this forum is that this event is somehow about saving energy. OK, it may save a tiny amount to turn off your lights for a few minutes, but that's not the point of the event. It is SYMBOLIC, a gesture to show that people care about air pollution and want the government to take action. And the reason it's lights out and not an air conditioner is of course so that people will be able to witness all the lights going out at 8pm. If you imagine the entire city going dark at 8pm: now that would be a great gesture. Of course it won't happen like that, but still.
I'm for putting away our jaded selves for another day and spreading the word about this interesting event instead. The very, absolutely worst scenario for an individual: you miss 3 minutes of a TV show and you're the only person turning off your lights so you feel a little silly. Damn.