You raise some valid points, and im not disagreeing with any of them.. - Not speaking for any one else, but my own opinion was that if their was an incident requiring rescue, within 30 km of the mount, and the fulltime crew was available, that it was my opinion they should be tasked.. (Along with which ever vol. agency covers that area also).
Only because they are there, they are available, and even if it was only day time mon to fri, a truck enroute is exactly that..! And those few mins saved can make a big difference.
Obvioulsy things would need to be worked out during the other times, as you stated, and that is where it would probably revert back to the local agencies who are probably slightly closer than that 30 km from the mount.
I don't think the 'second fiddle' issue would be too bad, as they would still be responded initially, but with the perm. truck tasked also (just ensuring a response).
Again, this only solves an issue for mon - fri during the day, and only if they are available, but at least during those times, if the system I mentioned above was in place, at least a truck would be going.
Im not sure how that would effect the agreement with the town coverage, I would assume it would go to retained till they were back in town?.. But who knows, they may have to stay and cover the town?.. Not entirely sure how it works down there.. My suggestion was just that if the Rescue was available, then it may as well be sent, as it is atleast getting a resource enroute while waiting for the vol. agencies who were paged.