How to cross the Congo-Cabinda border with this one weird trick! Health officials hate him!
The only time I've had problems was when coming back from Afghanistan... (KBL-BAH-LHR-IAH) we got 'randomly' selected for search in LHR, along with some mercenery looking dude, and got pulled aside for further questioning in IAH. We don't fit any profile though so the secondary questioning in the back room didn't take long.
I guess my Yemen flights were the a destination though, did open-jaw into Sana'a and out of Burundi.