Nation states exist in a state of nature, and unfortunately might usually makes right. Superpowers can, and often do, simply decide that aspects of international law just don't apply to them. Of course, that doesn't stop them holding weaker powers to those standards.
To be clear, I don’t think pilots should be in a position to judge the truthfulness of ATF or the government they’re flying over and I don’t think pilot judgment is the “solution” to this loophole that has now been abused twice (that we know). I’m just curious about the process and what would happen if a pilot decided to call the bluff. Would Belarus (or whichever country) scramble fighter jets to force a landing? Would the pilot get in trouble? Is the answer different for a private flight vs commercial flight vs diplomatic flight?
So IMO pilot could ignore their requirements and I think that nothing would happen outside of angry transmissions. Especially if the plane was near border. But I don't think that it would be reasonable, especially in an airplane full of innocent people.