https://www.cnbc.com/2018/01/04/white-house-is-cracking-down-on-personal-cell-phone-use.html

The White House will bar staff and guests from using personal phones in the White House starting next week.

The devices will no longer be allowed because "the security and integrity of the technology systems at the White House is a top priority for the Trump administration," press secretary Sarah Huckabee Sanders said in a statement Thursday.