I kind of disagree, in that any rule should have an implied "you can ignore this with good justification". Otherwise you turn people into robots, which renders moot all the reasons why you have people, and not robots.

I agree with this - in practice any rule can be broken - but how easily it's broken and whether developers are explicitly told to break it is a process decision. How big a roadblock is your CI putting in the path of developers? If you require e.g. sign-off from a team lead or manager or whoever has "merge anyway" permissions in GitHub, that's more difficult than sign-off from the same reviewer who's reading your code anyway. You can make it easier or harder to break rules and in this case I think it should be so easy to break that there's a codified procedure to do so.

I haven’t tried that - in that situation we did “find something that needs a test”