Laws are determined by the state, sometimes the county. By people. That's how laws work, they're just written rules, written by people, in this case, for the purpose of assigning ownership. As already mentioned, there are many different laws in the USA. We are not homogeneous.
Morality is determined by intent. Intent has not been determined here yet. If the "law" says that you can leave an old VIN ID on a part used on a separate car with its own VIN, then both of your cases are incorrect. The law will have been followed and whoever did it had no apparent intent to "steal" from another person. All they need to do is follow the law.
The OP has moved on, apparently, and may or may not be hiding the car for ten years. If he is hiding it then maybe he is committing an amoral act. But, he probably hasn't really though about it, so god might give him a pass.
Really though, you're kind of going over the top here. It's still just a car with some numbers attached, and no documents showing which are correct. Bringing the concept of a supreme power in to the discussion is a bit much, and nobody has advocated breaking the law. We're just describing how things are over here in the wild west. This is not England. But, since it's a topic, are the laws in all fo the territories of the UK identical, or are there differences? Might be a good point of reference for you. The OP bought an undefined legal problem and may or may not try to resolve it.
Found my example on Wikipedia. We're not so different. https://en.wikipedia.org/wiki/Law_of_the_United_Kingdom