Yes, you have to intern enemy soldiers that enter into the neutral country in order to preserve your neutrality. Spies are not soldiers, they are spies, and you

Yes, you have to intern enemy soldiers that enter into the neutral country in order to preserve your neutrality. Spies are not soldiers, they are spies, and you can't quite do this (especially not in practice), but you can pretty much shoot them as you like, even if they've surrendered (and since New Zealand and France weren't at war it was simply treated as ordinary criminality). They basically don't have any rights under the laws of war. The fact that I suppose it was a partially Germany-owned pipeline probably places the attack in the same framework as interdiction of neutral shipping. I suppose it's really a proportionality thing then. Was the destruction of the pipeline proportionate-- so I suppose there really is a case, with the arrest warrant then, being legitimate. Since there were alternative avenues-- demanding that the pipeline be cut off, proportionality is obviously doubtful.