I found that having a beard or long hair that is not military neat would get me a secondary every single time here at BOS. Although now I suspect I am on some kind of list since I get secondaries every time I fly even clean shaven and with a crew cut. I don't know how he was dressed but I would suggest getting a hair cut within a few days of travel, shaving with a triple or quad blade razor within a few hours of travel, and wearing a nice suit and tie. Although of course that is exactly what a real terrorist would do. Maybe the TSA will start putting barber shops under surveillance, monitor sales of beard trimmers, and start monitoring suit purchases. Any suits or ties purchased within a week of travel would flag you for a cavity search. Also he should avoid being in the sun too much. The whiter your skin the less likely you are to be a terrorist. Lucky for me I avoid the sun and am as pasty white as you can get. Although maybe being too white is also suspicious.