I still can not believe people are so close-minded. Gamma is NOT a means of artistic control. It is not like it is another tool that can be used. It is something that should be hard coded in most of the modern applications. With gamma you do not change just what the output is, you chose to display very different color range where for example sampler does not resolve noise. You can end up with a lot more noisy renders, or with totally wrong normal/opacity maps if you open them with wrong gamma. Or having post processed motion blur/DoF not working correctly. Gamma changes a lot more than just perceived colors.
For example, in Vray, if you have wrong LWF set up, you might end up with significantly longer rendertimes as adaptive sampler resolves noise at levels very different to those you perceive through wrong gamma. Use whatever works rule does not apply to gamma, especially now, when correctly working contrast function is implemented.
If you, even after this, decide to play with gamma, then fine. Just please do not mention it here as if it was just another feasible workflow, because it can confuse a lot of new users.