Mercenaries Run Amok

It's no secret that the third largest military force in Iraq is the army of military contractors, essentially ex-military personnel carrying guns for private companies. The BBC is reporting on a crew of former Special Forces soldiers recenlty arrested by Afghan authorities in Kabul, for reasons unknown, possibly at the request of the US military. The report says they found eight people illegally detained by the men at a house in Kabul. One wonders at the implications of this widespread use of mercenaries. How is their conduct governed? Certainly they ought to be subject to international law, but what of the codes of conduct of the US military? What sort of oversight is tracking the actions of these people? The article mentions that they frequently wear standard issue military uniforms and carry standard military weaponry, and that it is difficult to tell who is who and under what authority these various groups of armed men are operating. It seems a prime opportunity for confusion and lawlessness. And what of the concept of the government (whether domestic or that of an occupying nation) maintaining a monopoly on the use of force? I know that privatization is all the rage with current administration, but have we really thought this through?