I recall a story on TV a few years ago where the UN needed a vaccine for a fairly "common" disease (IIRC, it was the flu) that had started to spread in a country in Africa. The US Army had a lot of the vaccine stockpiled in Europe and offered it to the UN. The local UN chief refused the vaccine because he did not have proof of its effectiveness - the Army had used the vaccine for nearly 30 years.
That reminds me of the story of Bill Clinton refusing to catch bin Laden because there was "not enough evidence to convict him."
How much proof do these people need?