Though, on second thought, "government X could force Apple to disable feature for members of group Y" seems possible. I'm sure you can come with "Y" quite easily, heard anything about Ed Sheeran's tour?

I mean, the obvious one is that they can revoke certification of a photo despite it being real.

The harder one is they can force apple to certify a fake photo.

the part that would be very hard but not outside the realm of plausibility, is that gov could force apple to introduce a bug in its pcc platform to link photos to the photographer in order to track and arrest inconvenient people. Apple says there are a bunch of protections against that but ultimately you are trusting apple to do it the way they say they are.

This entire system relies on trusting apple

Apple would have to be the only company around and by the time Apple “loses” in court its too late.