In the case of Nature, it functions as a statement of values that scientists publishing with Nature will be happy to comply with to the best of their abilities.

In the case of Nature, it functions as a statement of values that scientists publishing with Nature will be happy to comply with to the best of their abilities. I doubt that the editors are under some illusion that the nominal ban will create a hard line in reality. I'd be surprised to learn that that is their idea of success with this measure.