You would attach your " firemark " to the building that you had paid fire protection dues for to indicate to firefighters that it was a "protected" building. There was strong competition among fire companies for dues.
I am the Chief of a small rural volunteer department in Alaska. Our first responsibility is to the fire protection district that funds us through its tax base. We could never morally refuse to respond outside our district, given equipment and manpower availability. We do have statutory authority and a mechanism in place to bill for such service. Surprisingly, most insurance companies will cover that cost.
The law may give you more protection up there, but I recall a case out of Tennessee where a department responded outside thier area, and was rewarded with a lawsuit from the owner of the building who felt that there was too much fire damage.