Unlawful in New Zealand. I'd be surprised if what they did wasn't legal under US law.
Correct. I was wondering the entire time reading the link what exactly was illegal since it is fairly common knowledge that all nations spy on each other and in the US it is totally legal for the US government to spy on foreigners who are not on their soil.
It's probable they do things that are illegal under US law, but I doubt this is one of them.