Ars Technica Live: What to do when border officials ask for your passwords
Found on Ars Technica on Wednesday, 22 February 2017

What exactly are your rights at the border, and should you really hand over your social media passwords to a customs agent?
If you're curious about your rights at the border, how ICE's future deportations will work, and the longest amount of time any US citizen has been detained by border agents, you need to watch this conversation.
Just tell them that you do not have any social media accounts. As long as "in dubio pro reo" still exists, they have to prove that you have accounts.