I don't think the reduced life was a specific US requirement - rather that NZ (the country) wanted to keep up with the security technology, so as to avoid in the future another occurance of things like the Mossad passport scandal, to ensure the "NZ passport is very well regarded" - "We intend to make ourselves a very hard target" and all that la de da..

I would have thought ajnz that the circuitry in the card didn't matter, it was the reader ? I remember there was some controvesy in the US about their new chipped passports to roll out soon (well they already have for Diplomatic holders/by October for the rest I would think - after all that's when the US requires every other country to have it done by ) - the vendor IIRC Infineon embedded a thin-metallic anti-skimming shield in the passport to try and prevent eavesdropping. They also have some system where the data on the 64kb chip is encrypted, with the unique code to decrypt the info located on the existing "machine-readable" panel of the passport, and done on the fly by border computers.