The information I got was the same as Carguiro mentioned. Anything that flags up is checked manually. Eventually he was boarded too and it is part of parcel of flying these days. Questions will be asked from everyone. I have been asked many times too why I was going to a certain place and then flying from a different airport. Best be honest and tell them. I would not say it is racially profiled especially in Asia. They have much more knowledge than in USA or Europe. In Asia it is profiled by nationality and the route they are flying.