Re: Photoshop Makeovers, at what point is a photo no longer a valid representation?

There’s been considerable buzz recently about Demi Moore’s re-touched photo on the cover of “W.” First there was outrage that her hip was visibly cropped, and later we learned that her entire torso image belongs to a runway model: 

http://consumerist.com/2009/11/great-now-demi-moores-torso-is-missing.html 

I just learned that the overwhelming majority of celebrity photos are somehow retouched in Photoshop: http://www.youtube.com/watch?v=YP31r70_QNM&feature=related 

At what point is a photo of a person no longer valid?