<blockquote>This could require people to hand over their phones so officials can study their stored contacts and possibly other information. The aim is to “figure out who you are communicating with”, a senior Department of Homeland Security official was quoted as saying. “What you can get on the average person’s phone can be invaluable.”

A second change would ask applicants for their social media handles and passwords, so that officials could see information posted privately in addition to public posts, the Journal said.</blockquote>
via <a href="https://www.theguardian.com/us-news/2017/apr/04/trump-extreme-vetting-visitors-to-us-share-contacts-passwords">'Extreme vetting' would require visitors to US to share contacts and passwords | US news | The Guardian</a>.