It depends on what you assign as a parent in the first place, and if that has a standard place somewhere in the hierarchy. For example, if you make a place in the ocean where there’s not a standard place, and then make smaller places and assign them to that parentless ocean place, if you delete parentless ocean place your smaller places wouldn’t have anything higher in the hierarchy to attach to.
But for your use case, as long as there’s a New Zealand-related standard place somewhere in the hierarchy, it shouldn’t end up completely orphaned and parentless.