Apparently a lot of folks entering the United States are being asked by Customs and Border Protection officials for the passwords to unlock their phones and laptops.
If you say yes, and you have the usual apps on your device, then CBP can suck down all your encrypted data in a matter of minutes - search history, contacts, photos, purchases, documents, social media posts, etc. - and store it in their U.S. government database, where they can keep it forever, and inspect it at their leisure.
If you say no, your devices can be seized, and you can be detained. Legal or not, this outcome will, at minimum, ruin your day.
Various workarounds have been proposed to keep the data on your devices private when entering the United States. These include traveling with -
No devices.
Temporary devices.
Wiped-clean devices (keep data in cloud).
Dead-battery devices.
Privacy experts argue in favor of doing this, and security experts argue against it, saying it looks more suspicious.
Arguments for workarounds:
https://medium.freecodecamp.com/ill-never-bring-my-phone-on-an-international-flight-again-neither-should-you-e9289cde0e5f#.wgurjewri
Arguments against workarounds:
https://medium.com/@thegrugq/stop-fabricating-travel-security-advice-35259bf0e869#.o43h5lbiz
What's HN's opinion on the best practices in this situation?