Every now and again the discussion flares up: is post-processing of photos allowed? The main problem is of course that "the belief remains that
when there are no obvious clues concerning image manipulation, the image must depict reality" as a student in Media from Amsterdam, Alexander van Dongen, wrote in his 2006 thesis, which I stumbled upon in the Net. At the same time: the charm of photography is precisely its 'believability', its truth-likeness. It would not be fun if viewers did not believe that the photo was real.
To me the issue remains contextual--and then it's simple: if you want to convey a message of reality, then no fooling around is allowed beyond general interpretation of the sensor data (i.e. making truthlike colours by adjusting the white-balance, adjusting erroneous exposure and the like). If the aim is just to please the viewer's eye, then all is allowed.
But we don't believe in the self-organising force of the market anymore: it has become only too clear that markets may be good at coordinating supply and demand of simple goods, but when cheating is possible, it will happen, so that controls on honesty are necessary. Newspaper editors, photo award juries etc. are the public's agents in that respect. How they make their "contracts" with photographers, may be an interesting question for researchers of property rights theory, or principal-agent theory. For me the poitn is: I want to trust my newspaper--and I want to enjoy pictures at an exhibition for what they are.