some trips are planned long before the outbreak of the swine flu, involving many agencies from Singapore and the place of destination. Its not easy cancel/postpone them, and doing so would cost the organisers , participants and the many different agencies/embassies a huge loss of $$, not to mention the organiser's reputation is at stake.
So is it really more selfish to go ahead with these important trips? i dont think so.
In retrospect , it is often easy to see that the cost of the trip outweighs the benefit. But , at the point of making the decision it is very easy to underestimate the risk, especially when the govt lowered the alert level.