I think they even do that in some DEA operations and even some FBI operations,i think it's to preserve their ability to go undercover possiblt in the future.Also in Iraq I would think it would be necessary to protect their family also.
They must wear the masks to hide their identity from the terrorist who would target their family.I hope we can get these guys some better vehicles soon.I wouldn't want to be driving around in the back of a pick up.