in regards to the preemptive call:
First thing to know:
My airspace is large, several times larger than than the country large. My airspace has boundaries with Brisbane, Jakarta, Colombo, Male, Mauritius, Johannesburg, Antarctica and New Zealand. It also covers most of Western Australia, takes 23 frequencies to cover it, and it takes a 777 6+ hours to transit.
Second thing to know:
We have to coordinate details of every flight that enters or exits our FIR with our international partners. This is usually: Callsign, Boundary position, estimate and flight level. Sometimes more details if the other FIR doesn't have the plan. All this info also has to be read back to confirm correct.
Third thing to know:
It's not uncommon to have jurisdiction of 30+ aircraft and have no one within VHF coverage. All the communication is done with CPDLC and HF relay.
All this means that even though you might be the only aircraft in the state on frequency and it sounds awful quite, we can be working pretty hard in the background.
The eventual point is this:
Most controllers don't have to do all the coordination that my group does but if I'm listening to a coord readback from another FIR and an aircraft jumps straight into a long winded call it means firstly you're going to get told to standby, then the other FIR controller is going to have to readback all the info a second time so I can confirm correct then you're going give the call a second time. Not only wasting your time and my time, but the time of an entirely different FIR.
While it's perfectly fair that it's not for every controller, if you're in my airspace (250nm outside PH north and east. Kalgoorlie to Port Hedland), give me a heads up.