New submitter mendred quotes a report from Mashable: Celestine Omin, a software engineer at Andela -- a tech startup that connects developers in Africa with U.S employers -- had a particularly unwelcoming reception when he deplaned at John F. Kennedy Airport and was given a test to prove he was actually a software engineer. A LinkedIn post detailing Omin's challenging experience explained that upon landing in New York after spending 24 miserable hours on a Qatar Airways flight, he was given some trouble about the short-term visa he obtained for his trip. According to the post, an unprepared and exhausted Omin waited in the airport for approximately 20 minutes before being questioned by a Customs and Border Protection officer about his occupation. After several questions were asked, he was reportedly brought to a small room and told to sit down, where he was left for another hour before another customs officer entered and resumed grilling him. Omin was instructed to answer the following questions: "Write a function to check if a Binary Search Tree is balanced," and "What is an abstract class, and why do you need it."