[angkor]

They did this in Indonesia after the Bali bombings.

State Dept. is not normally very prescient in anticipating actual dangers, but who knows, they could have something this time.

I've personally heard State employees declare "everything is A-OK" when I knew there was shooting happening realtime only a couple miles away.

[kabar]

Many ambassadors are hesitant to request an evacuation of mission personnel. In some cases, they are concerned about the signal it sends to the host government. There are also legal and contractual ramifications related to US companies doing business in the country. An evacuation could trigger a withdrawal of private contractors affecting their businesses. In Iran in 1979, Amb Sullivan objected to an evacuation of mission personnel and was overruled by Washington.

In other cases, Ambassadors see an evacuation as a personal reflection on them and their relationship with the host government. Many times, the host government tries to weigh-in against an evacuation because of the domestic impact. The bottom line is that there are many factors and considerations that go into the decision and it is not taken lightly.