My take is if the assets are those of a fully developed women with a young looking fade or a "story" that she is young, I am a little less concerned, but if the anime girl is like pre adolescent, then that is a serious problem. My logic is that fully developed women with very young faces are, the vast majority of the time not minors. But if you take away the adult development, then nearly all of the real world examples are minors. And that there is time for some serious ass whoopin.
I myself don't like anime mainly because they are trying to blur the line a lot (and sometimes just flat put crossing it). I don't need that in my life.