Re: This has been a policy since at least 2008
That is new, and it's all Trump.
Male Bovine excretment
Look at the New York Times dated June 28 2016 ...
WASHINGTON — The federal government has proposed adding a line to forms filled out by visitors to the United States that would ask them to voluntarily disclose their social media accounts, a step that it said would help in screening for ties to terrorism.
or there is Politico 22/12/206 (before Trump was sworn in for those who need to remove shoes to count to 20)
NEW YORK — The U.S. government quietly began requesting that select foreign visitors provide their Facebook, Twitter and other social media accounts upon arriving in the country, a move designed to spot potential terrorist threats that drew months of opposition from tech giants and privacy hawks alike.