[_acme]

Unless NZ is significantly different from most other countries, no one has a right to a resident visa (although some people might have a right to citizenship, such as by descent), so they can already arbitrarily determine whether or not to grant a resident visa.

[lopmotr]

Sure, but in practice, they don't seem to do that. I've heard of public complaints of denials and it's because the person doesn't actually meet the published criteria, not just "they seemed a bit scary".