[Mr Guy]

Two things.

First and foremost, you need to turn off full size images in smugmug. There's absolutely nothing preventing them from saving those pictures and getting them printed themselves. There's a setting in Customize Gallery to set the largest size to anything from Medium to Original. Anything above Medium is asking for trouble. The right click prevention does nothing.

Secondly, what exactly did they purchase from you? You keep mentioning prints and enlargements, but then talk about the color calibration. Do you mean the color calibration for the gallery themselves? I can see where she may be coming from regarding the lips, but that's pretty obvious in the online gallery itself. The one complaint I'd have with your entire gallery is strictly a matter of taste and preference: I think they are all on the side of over saturation. Not so severe as to be unpleasant, but I think you could take it down a notch and not lose anything. However, the fact that she's complaining about that in ONLY THAT PICTURE screams to me she's full of crap. The saturation and color skews appear to be extremely close in all the pictures, if she didn't like that style, she should be noticing that in every single picture. Since she's not, my money is on either deciding later she preferred a different picture or she's trying to get free stuff. Neither of which is your problem.

In the interest of your reputation, I'm inclined to think you are best off standing firm on offering reprints (after the original is returned) or selling (not giving!) digital copies.