Jeez man. You are all over the road.
The question is whether the statement "Legal is the default state for devices that don't use public roads, public airwaves, etc" is a form a No True Scotsman. You are saying that the answer is "no," because this concept of "legal" is something that you attribute directly to the statutory authority of government alone.
The goal posts haven't moved. My hypothetical describes perfectly the state of the internet today: a bunch of governments claiming authority various realms, and worldwide confusion about what 'the law' is or how it is defined and decided.
You won't be taken seriously by saying, "I have decided that a huge open question in political science is just a simple matter of declarative fact that I need not consider." I mean... do you not realize how ridiculous you sound?
If this 'simple fact' that 'the law' is so easily defined and understood as a 'popularity contest' is self-evident enough to warrant this kind of 'case closed' mentality, then why have the greatest minds in the field been wrestling with it since ancient Greece?
If you refuse to consider the question, then of course you get to make up the answer.
So go ahead. The answer can be "yes," "no," or "unknown" depending on your mood, and you'll always be correct.
Your laziness vis a vis reading the seminal works of law has not only the consequence of making you seem stubborn and misinformed for the purposes of this discussion, but also unfit to be an effective citizen generally.
If you can't bring yourself to participate in even elementary academic discussion, why even visit this site? Just to raise your blood pressure?