Kiwis get a "visa waiver" issued when we land. We need to fill in the form declaring that we aren't nazi war criminals, aren't members of Osamas immediate family, love apple pie and that yes we agree gridiron is better than rugby etc.

They also need SOME contact details for the US, as do most countries. Its no biggie but it does get put into the computer so it needs to be legit(I've been questioned about trips several years later!). Its probably in case someone on your flight had bird flu or whatever.

Its all a formality and travelling on a kiwi passport anywhere is usually like that (which is probably why the Israelis send the mosad to NZ to get passports!). You might need to prove you can leave the US under your own steam too.

Of course if you look remotely like a terrorist you might have problems.
You will almost certainly get randomly selected for extra security screening when checking in for the DC flight too, regardless of what you look like.