Actually, I mean... to a point, yes? If a piece is clearly overly stylized, that's one thing, but while this piece does have a painterly aesthetic, the style is still quite realistic. Artists generally need to have a pretty firm grasp of light, reflections, etc. And if they were going to go to the trouble of putting a reflection in her eye, I'd think they'd want to get it right.
I don't think asking an artist to be proficient in physics and the laws of nature is a valid request, however you want to put it.