I'd wear one just to piss off my boss. (It would be worth it.) I've lived in the US since I was about 12 and haven't been back in about 10 years. I also served in the US Army for about 5 years so you could say I'm a little confused on where I stand on nationality. Anyway it would be worth pissing my boss off with an All Blacks Jersey.
I've lived in the US for 21 years and will still never wear an All Blacks jersey. The only way that would happen would be if had a choice between a Bosox and a Kiwi shirt. Trust me, the Red Sox shirt would become toilet paper first.