Let's put this in a perspective you might just understand. Let's say you meet a man who has a 23 year old son who has become a rather radical Muslim, has taken Al Qaeda training in Yemen and has expressed a desire to kill infidels. His father has reported him to the authorities, but they have not revoked his visa, nor put him on a no-fly list. You see him in a rest room at the Amsterdam airport stuffing a package into his underware. What do you do? The authorities have already shown a disinterest. Running to security is pointless.