The busiest border crossing in the world is here in San Diego with Mexico – 100,000 people go through this border everyday.  Due to the swine-flu threat they have begun “passive monitoring” – that is use subjective judgment to visually determine if someone is sick or not and then pull them over for further evaluation.  This seems way too low-tech and inaccurate compared to Asian airports that use thermal monitoring cameras to identify people with a fever.