So if it's got a red cross you can't put any sort of defensive weapons on it?
Here is what I got from some phrog guys whose squadron deployed as a CASEVAC unit. The Navy is working under the Army protocol. Red Crosses, no crew served weapons, Dust Off call signs. When the Marines deploy they take the same missions, but they do not use the Dust Off call sign. That is because when the Army asked for help with Dust Off the Marines declined to play their game unarmed. So, it is CASEVAC for the Marines because they are armed, Dust Off/AA for the Navy. I expect that is because the Navy was so happy to get the invite, they just went along with the Army program. They should have held out for the .50 cals in the doors.