Put them in a room with a video from the Middle East that shows a woman in a full burka being whipped by an old drooling guy with a long beard. If they act aroused, they are terrorists. If not, don’t let them in anyway because ISIS trained them well.
That reminds me of a line from the door gunner in Full Metal Jacket: “Anyone who runs is a VC. Anyone who stands still is a well-disciplined VC.”