Pretty quick, they seem to have put the whole stunt together in a single day, if the real Chevron campaign was launched on the 18th.

From the fake press release:

"We were asked to show an agreeable, involved, of-the-people face for Chevron, and we think we came up with some really great ways of doing that," said Gordon Bowen, Chief Creative Officer of McGarryBowen. "But what’s unique and different here is the honesty. We've never been able to do this before."

I've watched the Yes Men movie premier at Sundance Film Festival, it was incredibly funny. I think it is out on DVD now.

If you look at the real ads, you can see they are crying out to be spoofed:

http://www.chevron.com/about/advertising/

They were the same people who went on BBC, posing as spokes people for Union Carbide and promising that they would finally pay a decent amount of money to the people who where hurt by the Bopahl disaster.

It might seem like a nice stunt, but it hurt a lot of people who where hoping that they would finally be given some help and Union Carbide didn't really care.

I've been following the antics of the Yes Men for a long time now, and I've always been stunned at the kind of moxie it takes to get away with the things they've pulled. I've really appreciated not only their message, but just the sheer bravado it takes to go to a conference posing as a WTO spokesman and, with a straight face worthy of an oscar, proposing to the audience things like an economic marketplace where shares in human rights abuses are traded.

Appearing in newly purchased suits, the Yes Men gave speeches encouraging corporations to buy votes directly from citizens. They argued that the US Civil War was a waste of money because Third World countries now willingly supply equivalent slaves. They also urged people to listen to the WTO instead of the facts. They then unveiled a gold spandex body suit that they claimed would allow productivity to increase, as managers would not have to oversee workers in person but could keep track of them via images on an attached screen as well as implanted sensors. - Wikipedia

Their website seems down but if it comes back up soon, consider helping them out in their Yes Labs http://theyesmen.org/lab .

The parody ad is interesting, but spoofing emails from real people seems to cross a line from novel protest to nasty malicious behavior.