Upload everything to a server before you leave. Download it when you get there. Take no devices across borders except a throwaway phone for emergencies.
It's not clear, however, why if customs can demand your passwords to your devices, why can't they demand your passwords to remote servers?
In any event, it is important to protest in the strongest possible way these encroachments upon our individual liberties. It's shocking that this needs to be repeated in 2013 in the West, but a citizen should not be deprived of life, liberty, or property without due process of law, and mere suspicion does not constitute due process. The state cannot be allowed to continue violating these rights.
I've spent some serious time in NZ, and was deeply impressed with the humanity of it's government and it's governmental workers. It is heartbreaking to see this Americanism make its way to a more innocent land.
Don't give in to this, Kiwis. Protest. Write letters to your representatives. Keep your dignity and your common sense. Don't let your security forces (at the border or anywhere else) do this sort of thing to visitors.
I don't know that there's any legal mechanism in their favor (I'm not very familiar with NZ law on this level), but there's a simple physical mechanism they have going for them. If you refuse to provide passwords to your devices, they can simply refuse to return them to you when they're done with their "inspection". If you're a citizen and you refuse to provide passwords to remote accounts, they have no lasting leverage. If you're not a citizen, they can simply deny your entry.
Edit:
> I've spent some serious time in NZ, and was deeply impressed with the humanity of it's government and it's governmental workers. It is heartbreaking to see this Americanism make its way to a more innocent land.
Two things... First, this is the kind of thing that had us moving there in the first place [Edit: for clarity, this wasn't an initial reason for our move, or even why we selected NZ, but it's definitely in the "pros" column]. I'm displeased with the adversarial/entitled tack that my country's government sometimes takes with its people, and I'm still hopeful that this is different elsewhere.
Second, I find it really sad that you'd label this "Americanism." I don't think it's entirely inaccurate to say that this is becoming a part of our culture, but there is still tons and tons of good which can be ascribed to that label as well. I hope that the bad isn't dwarfing the good to the extent where the term "Americanism" becomes synonymous with "McCarthyism."
New Zealand law does, in fact, allow this in certain cases, albeit not in the one Customs are claiming (objectionable material, i.e. porn).
FWIW, my wife and I were in the middle of a move to California to work for Google, and we decided we didn't want to do that and that we'd rather live in NZ instead (I'm a kiwi but had lived overseas for 13 years, she's foreign produce). I've been very disappointed with some of what I've seen from a legal/political point of view since I came back but NZ is still streaks ahead of most other places I've lived from a quality of life standpoint (with some exceptions, primarily cost of living will shock you coming from the States). We're really happy with the decision we made and I feel like we have a much better life here than we would have had there. Where will you be living?
I hope that the bad isn't dwarfing the good to the extent where the term "Americanism" becomes synonymous with "McCarthyism."
Sadly, between the NSA and the TPP, as a foreigner it's getting harder and harder to see the good of the US. I'm afraid that in my experience your whole government and system of governance, at least, is getting tarred with your foreign policy brush. That said, I don't know any Americans who have experienced any sort of personal issue with the people they meet here because of this, but the country itself is not seen as an agent of good IMO.
McCarthy has been dead for a while, and this stuff seems to have support from both major political parties in the US. And the US really is trying to make these sort of invasive policies into a new global standard. (And not just here; look at all those new trade treaties, at the blind loyalty to corporations, etc.)
I'm afraid that "Americanism" really is turning into a negative thing.
Because they can't read my thoughts? At least yet :-)
Seriously, if you have a VPS and remember the IP address or the domain or whatever, how can they find out? Don't use SSH keys and/or delete the known_hosts entries. Use a password to login to the server. Voila.
And before you argue, "Well, they'd never use that for something so trivial," remind yourself of what you used to believe that the government would never do. (And I wonder today how many people are accused and convicted under that particular law.)
Unless someone already had passive/active access to your machine before you left, they won't be able to get at your data.
Your restore should be fine, too. Just watch out for passive access being added by the tech teams inspecting your machine (say reinstall-persistent malware) - though this shouldn't happen in the majority of cases, we'd hope.
Security.
Job security.
Potential political prisoners - what else? They're only ever interested in anything that could constitute a threat to their power, however mild. It's also about conditioning us into apathy / obedience / accepting serfdom.
The original article mentioned the guy had been to a conference on surveillance, right? They know he's an unharmonious little tax slave, a potential troublemaker! That's why his devices were confiscated, not any suspicion of "terrorism" or whatever.
In relating to the other story about secrets, what do we really have to hide that we don't want the TSA to see?