(I quickly changed this to round three. Feel free to share.)
No, we don't want an opt-out and actually not even an opt-in (even if this would be far better).
What we actually want is ART on ARTstation which excludes A.I. pictures.
If you want to see my art, (I unpublished my portfolio here as long as they support A.I.), you can find it here on instagram: https://www.instagram.com/sandra.suesser/