Sadly, the same old argument holds true. There is no way in hell that CFS can guarantee a response to any emergency at anytime. That is merely how a volunteer organisation works.
I know that the special people from Mt. Barker will no doubt yell, scream, hoot and holler that they can get two trucks out the door, therefore they deserve to remain volunteer, but if they really worried about the community, they would be supportive of a move to have full-time SAMFS staffed stations in their area. Keep in mind, by the time they get to the station itself, a full time station would already be on the road...
The same thing holds true in all built up urban areas, Mt. Barker, Seaford, Mt. Lofty Group. Nothing can guarantee service like stations staffed 24/7.
Don't get me wrong, I love the SACFS angle on things, but at some point we all have to think out a bit further than just ourselves.