in my opinion this would be hard to implement as most of this is done within DMs and Discord, so expecting artists and/or sellers to be responsible and liable would be necessary, and if you have already people selling the same thing to different clients they know they are doing wrong and wouldn't disclose it lol, there'd need to be policing.
I think a system that monitors the files/images that are uploaded would be more efficient and could be studied, so you'd not only knock down art fraud but also plain art thievery in one stone.