Apple doesn’t refuse when they can “unlock” a specifically requested case.This is a delicate subject, but someday if we ever have a serious real-time pending catastrophe and the only way to resolve the pending catastrophe is for Apple to "break into" an iPhone and Apple refuses, they will have hell to pay.
What so many don’t grasp is that good security is not breakable by those who created it. If they can, they failed.
(I write iPhone security software.)