[mannykannot]

The original question is not intended to be considered as a rigorous argument, as its author made clear. My point of entry was to introduce a fact that answered your specific question, and as far as I can tell, it stands as such.

While the law, for obvious reasons, rarely uses 'I know it when I see it' justifications, I suspect that that is what most ethical principles ultimately depend on, and to the extent that the law tries to be ethical, the same goes for it.