...is that everyone has the same ones.
Reading Defense Tech (as usual) I came across this quote about Israel using undercover special-ops teams who pass for Palestinian:
Of the 2,200 arrests Israelis made in the West Bank last year, about 1,500 were conducted by special operation forces (SOF), including 366 by a special Arab impersonation unit, he explained. These specially selected and trained personnel have demonstrated the ability to completely blend into the opposing population for intelligence and operational purposes.
It reminded me of a passage from Tony Geraghty's Inside the S.A.S., about the elite British commando force:
...in the foetid alleyways of Aden itself the [S.A.S.] had its first taste of urban terrorist warfare...the launching-pad for clandestine plain-clothes operations...
The basic concept in Palestine and Aden, quite simply, was to blend into the local scenery and seize on targets of opportunity. The men chosen for this work were those who most closely resembled Arabs...The next criterion of selection...was the ability to draw the heavy, thirteen-round Browning pistol from the folds of an Arab futah, and fire it with perfect accuracy... Their main quarry was the group of skilled, Yemeni-trained assassins...
The more things change, the more they stay the same. If US troops in Iraq aren't doing this yet, they will be soon.