The problem is, `/docs/plan-to-hijack-airnz-plane.txt` can easily be downloaded from the cloud once you're in-country, so you can just not keep it on your phone. This is a significant difference compared to bring in explosives (as an example), where searching your luggage would actually be effective.

Again, this law will primarily inconvenience / harm law-abiding folks, while not preventing the "bad guys" from doing what they want.