I am sorry, but I may have misspoken. It is not a cost issue but a matter of risk management. As I explained earlier, the mandatory reporting of a sick person on a plane or a ship is to make available the necessary resources at the point of entry. If someone gets ill on a bus, there should be hospitals and medical services providers on both sides of the border. It is a matter of practical management. If a person gets sick, it is possible to disembark him or her in another city before arriving to the border and to have a follow-up. There are many such possibilities. However, when it happens on a flight, it is only possible to act after landing and this is why there is mandatory reporting. This is to ensure that the required measures will have already been put in place. Is this clear enough?
On April 18th, 2007. See this statement in context.