I think if you are aware of the things you are overstepping in terms of work, and fully know and why you are doing it. Then that feels more forgiving. For instance if you know and are aware of a lighting situation and know how to do it because of past experience then it should be more forgiving to take a short cut.
a few years ago over at cgtalk , when digital art was really booming and growing, some people even considered using reference as these guide tools .And some images and artists were really put in a spotlight because of either denials or admitting to using it. Now a couple years after in the digital art world it's just simple copy/paste techniques.So there is not even so much effort put into studying and replicating reference.
I think it's a bad habit for an artist to do that for over a long period of time. Instead of sketching out ideas and bringing them to 70 ish percent completion most of the work starts by finding base photos to construct the artwork on top of.
And that i personally feel is hard to call a work of your own, unless you took the photos yourself of course