how much of the work can be ai generated, would a minor human copyrightable addition to the artwork constitute an original work. what would stop someone from ge

how much of the work can be ai generated, would a minor human copyrightable addition to the artwork constitute an original work. what would stop someone from generating art and popping a watermark or some imperceivable steganographic addition such that the ai part and human part cannot be disentangled.