A tag that needs to be set in order to be opted out of training datasets is not acceptable. If you're going to add a tag, it needs to be set on by default. But this "NoAI" tag is not enough; Artstation must take action against users that post machine learning generated images. Artstation is a portfolio site for artists. If this site continues to be flooded with these images, it will drown out real artists and make it harder for us to get noticed in a sea of machine-generated dross.
Artstation, protect your users. Ban machine-generated imagery from the site, or at the very least, sequester it to it's own section.