My understanding of PANS-OPS (the law)
Begging to differ, just slightly, PANS OPS itself is not L.A.W. Law. It is nothing more than a "Document" issued by ICAO. The way that it, or even TERPs, is made into law is by local legislation. Every regulator is entitled to make changes to it that make it applicable to their own environment. It is a
HUGE mistake to think that PANS OPS is law because it is not.
Many States adopt it entirely and without changes. Other States, that think a bit about how it impacts on their environment, make changes to suit their own operational situation. You find this out through each State's AIP or the Jeppesen pages (or other providers too, of course).
There is a legislative background to it but PANS OPS itself cannot be used as a legal basis by itself.