AC provides a pointer to a news article
about the possibility of using private military companies (PMCs) in Darfur. As the new Iraqi government exerts more control over private security companies (as well as the country moves to the brink of civil war), businesses such as Blackwater are starting to look for new sources of revenue. Conflict zones where humanitarian operations are taking place are being viewed as likely opportunities. The prudent NGO security officer should start learning about how PMCs operate. It seems quite probable in some locations that whether they like it or not, PMCs and NGOs will be working side by side.
Postscript: Here's a link to a recent article that debates
both sides of using PMCs in conflict zones.