There are ISIS cels in the UK, obviously involving UK citizens, some of whom were killed as perpetrators of terrorist acts in London.  But, no ban on travel from UK. . . The Philipines has an ISIS onslaught going on on the island of Mindanao.  The Boston bombers were US citizens.   Have to wonder exactly why the US is concerned with Syrian grandparents.  The travel ban is only about terrorism in written justificatiion.  It is the MUSLIM BAN Trump promised, designed to appeal to his base.