I used to get stopped for further inspection every time I cane through customs in Detroit. I guess I fit the profile. (a single male traveling alone from "suspect" places like Mexico and Thailand.) Then one time the customs agent asked for me to place my bags on the table and ran my passport. He then smiled and jokingly said to me, "We do this to you every time don't we?" He waved me through and I haven't had them stop me since. This happened about 9-10 years ago.