There was never a negative leap second, so most systems are not ready for it. It is not just a question of time metadata.
And cooperation could be a problem. I can not imagine Microsoft providing updates for illegal Windows 7 in North Korea, and NK government just taking them.
Electricity exchange grid needs to be phased within 60Hz, that is a delay of a few milliseconds. Baltic states hate Russia, but they are still connected this way for example.
Maybe you do not care, but this stuff is extremely important. Airplanes could crash over a few seconds difference!
> Electricity exchange grid needs to be phased within 60Hz
Electric grids also make use of DC interconnects that obliviate the need for that synchronization. The contiguous 48 US states have at least 3 separate grids that are interconnected. Roughly east/west/Texas. There may be more, but I'm out of touch with it.
https://arstechnica.com/science/2022/11/network-crashing-lea...