No, it's certainly not perfect. But, not being aware of a solution that's perfect, I've had to content myself with something that's merely better than anything else I've tried.

I generally like to have feature flags default to true in tests. It helps avoid this sort of situation, because if they ignore the flag, they’ve probably broken some tests. And if they only put it in the flagged path, their code won’t work in prod, but it probably won’t break anything either.

At least they can see it, instead of the code being in an entirely different branch.