However, non-travel-safe vaults a) won't show up on your devices, so they can't ask for what they don't know the existence of, and more importantly b) there is no evidence on the device of "hidden" vaults, or that you're in travel mode, so they doubly don't know the existence of those vaults.

So, if they take the actual password, as opposed to having you log in for them, then they can easily go to 1password's web interface.

I'm not sure if there is a legal barrier to taking that step, but there is no real barrier there if the credentials are the same.

Perhaps if there were also travel credentials, that would be useful. With the travel creds there would be no indication that you were in travel mode and no access to additional data.

Both can be defeated (they can detain you at the airport for a whole day, or they can spoof GPS) but neither of these mechanisms holds up to mass surveillance: you can't detain everyone who goes through the airport, or even all people with 1Password, for a day, nor can you spoof GPS at the security checkpoint because it'll probably leak to airplanes. You have to pick individual travellers and put them in a Faraday cage with a Stingray and an internet connection.

I'm not sure what the threat model really is, but it's possible that this will require enough time and resources to disincentivize asking for even more passwords when there's not a very specific suspicion, which might be good enough.

If you are a foreign citizen, you are looking at about twenty four hours, and then refusal of admittance.

This information is the case for keeping a cheap back up device(s).

IIRC, the border agent has the power to turn you back, visa or no visa. So there might be a price to pay for getting too cute. They want what they want and trying to avoid that might make them angrier.

If you are a US citizen they can make you wait in a room for a few hours and maybe add your name to the "make his life miserable every time he flies" list.

It looks similar to hidden partition in TrueCrypt

Of course, you do need to be able to log in to turn travel mode back on, so if I were to use this I'd probably do something like set up a service to securely send me my account key after I'm expected to have finished crossing the border, or maybe just store it on a remote server that I have access to under the expectation that the TSA can't demand that I SSH into a remote server (especially one they don't even know about). Though if I'm traveling alone (instead of with my wife) I'd probably just call her and ask her to turn travel mode off for me.

I'm not sure what you mean. I don't think it's unreasonable for anyone, migrants included, to tell CBP "I don't feel safe traveling with sensitive data, so I don't have any of that data on my computer". What's the 'gotcha' here? CBP isn't the only reason to want to have Travel Mode, there's also the increased risk of having your laptop stolen or misplaced.

> Only if you know them. ... You can't log into the website without that account key.

To mean that you'd openly have access to information in front of the guard, and then let them know that you can't access it at this time because of your elaborate scheme (e.g. tell them that it exists, but that they can't have it).

That's quite different to just not travelling with the data (or evidence of it existing) at all.

> CBP isn't the only reason to want to have Travel Mode

No, but it's the only 'reason' that's likely to use serious, life-altering coercion to make you to disable it, if they detect that it exists. It may be better to have no data that suggests capabilities, than openly posses partially disabled capabilities.

There's no way for a border agent to tell if you're refusing to disable travel mode because you won't or you can't (and little reason for them to care).

Nobody will ever do this.