The article link below is to a paper about the process that led to a figure of 800,000 murders in Rwanda gaining currency as an established, factual statistic. In fact, it seems to have had no factual basis of any kind.
Much the same thing appears to have happened repeatedly throughout the Balkan conflicts.
The dangers of taking information at face value are clear. High standards of fact checking and evidence-gathering should be demanded before conclusions are drawn.
Not only politicians and journalists are to blame (though they are greatly to blame). NGOs and ordinary people have also become too ready to accept victim testimony as being somehow sacrosanct. Even the legal world, especially flawed legal entities like the ICTY, has started to compromise fairness by decreeing that some testimony should command instant belief and should require no corroboration. This single step destroys justice.