Selective saturation raises issues in the Department of Photography Ethics Department. Because you can adjust a certain color's saturation globally, it can fall more easily into the category of acceptable adjustments in reporting or documentary photography. Consider this situation: you take a photo where the background has a strange color cast that you did not see when you shot it. Happens all the time since our eyes don't see color the way the camera does. If you correct the unwanted cast in the background, aren't you making the image MORE ACCURATE to the way you saw it and others would have seen it?
It is arguable that to adjust this is more accurate reporting. On the other hand, selective color saturation (or color shifting) can clearly be overused, or used in ways that are misleading. What else is new?
Bottom Line: Selective color saturation can be either a powerful tool for getting more realistic images, or for achieving entirely un-realistic creative images.
Some things can NOT be corrected this way. In this photo it is not possible to adjust the color of the wooden post without also adjusting the color of Nicole's face: they are light and dark shades of the same color. You would need to use local pixel editing to separate the post from Nicole to adjust them separately. Even if this hand-work made the photo more accurate in relation to the actual scene, would a strictly photo reportage venue, like National Geographic, use such a method? I would guess not.
5mm, f 1.2, 1/2000, ISO 100