This artist recently made a post on his Pixiv complaining about people uploading his works to other sites without permission.
He didn't mention which sites exactly so I don't know if he meant Danbooru, even though we only have a handful of his works.
Not sure if we should make A-801 a banned artist now.
Edit: Looking at the comments posted on that linked page that appeared during the day. Seems someone has been posting paid artworks on another site. Looks like this has nothing to do with Danbooru after all.