The second situation is a tough one. I think the main question that answers the rest is this. Does Nuuk break rule 15? And thus Casino would then be exonerated for his rule 13 breech by 64.1(c).. Casino has no way of knowing that Nuuk is going to duck and to be protected by Rule 15 must at least attempt to keep clear. Now the counter argument, What is Casino best option to keep clear? I can see the best way to keep clear is to keep his course or maybe even head down to clear his stern. Now on a computer game with limited views, I see it being very hard to make that decision quickly enough. So while I can go either way, I would lean towards a Ruling that looks like this. Rule 15 to Nuuk. And a rule 13 pen to Casino but is exonerated under 64.1(c).
Again it's kind of a complex situation in VSK because of communication, view, and lag issues....Now if we want to make it even more complex we could inject Rule 14 to the discussions (I know this taken out in appendix D for VSK but it would change things a bit I think)