Are you saying that ungreylistability/unknowability is impossible? That’s a strong statement that you need to support, but I see no such support so far. And if you believe that to be the case then what are you on about? 
I suspect that a host, or anyone, cannot prove that he doesn’t know something, such as the origin of a data chunk, but it is enough for our purposes simply to make it sufficiently expensive that no-one will try to find out that information. “One way or another”, that will surely be possible. I argue that it is essential, in order for SAFEnet to fulfill its destiny.