I would never mirror an image - but that might be because I'm a journalist, and it's an unwritten rule in journalism that you should never mirror an image of anything - it's changing reality. Then again, so is removing licence plates and badges. But I think mirroring should be avoided.
In my time here, I have posted two pictures of Alfas in which I have erased the scudetto. They are hereby attached. In one case, I admitted that I had done so before people started guessing, in the other I didn't. I don't see this as altering the appearance of the cars dramatically in any of these cases, as the scudetto is in neither case extremely significant to the car's design. With other cars, like the new Alfa 8C or the classic 6C, I would never have done it, because the design of the grille is an important part of the design.
Which also means that I'd think differently about erasing the BMW kidneys of an E30 3-series than doing the same with a classic, 1930s 328.
And in my opinion, it's one thing to erase something, and a quite different thing to replace it with something else. You could just have blurred the wheels...?
