One of the neat things about "artists" is that they rarely agree on onything!  

From my point of view, you simply click "nudity" if there is a question of any kind. 

Nudity is indeed offensive to some and they refuse to even look at it.  To others it is a flag to look!!   I have seen posts/art where nudity was marked and  the artist was taken to task  in the commentsfor checking it because there wasn't really any!   Go figure!

ArtPearl: your first image should indeed have been flagged "Nudity"  because it "portrays" such even though it hides what we normally think of as involving nudity!  .  (incidently it is art and I thought pretty well done).

I think you may be flogging the nudity issue with a dead "Naked Maja".

!