OK - that was shorthand for "individuals who present evidence that they need further scrutiny". Every day immigration agents make decisions about who they're going to take aside for any number of reasons - problems with documentation, odd travel history, flying AMS-LHR on a Sunday evening while being between 20 and 25 years old (been there!), I've seen reports that in at least one airport they watch people's feet while they're standing in line, you name it. Mrs. Milepig was once questioned when we flew the outbound together and she flew home by herself before me. They actually asked "Where's Milepig." To which she wanted to reply "I left him behind to fend for himself."

They're trained to sniff things out, and this couple passed the sniff test.