By that logic they could demand live access to your bank/social/email account as well. It's one thing to search things that you physically bring into the country - this article was talking about NZ only search the phones in "Airplane" mode.
True, the way this law is apparently defined I think you could get away with it, but the distinction between what's on the device and what's in the cloud is getting fuzzier all the time, and I'm not sure other countries would feel so constrained.