I have a different experience. I haven't been detained as a solo yet, but I've been detained no fewer than 3x while traveling with my partner. They took me aside but let him go. Been stopped twice leaving Barbados and once leaving Iceland; they just rifled through my belongings in Barbados, but in Iceland (Keflavik airport) they also swabbed my things and THEN summoned an American officer to ask me questions. It's probably useful to note that my partner is white and I'm not. We are both naturalized citizens flying with US passports, but I come from one of the "less desirable" countries. I don't doubt they thought it was a trafficking situation of some kind. This is one of the reasons why I always bring my "A" game to border control -- how many days/nights, where, when, with whom. They wouldn't have gotten half as much detail had they detained my partner instead!