Actually, it IS a difficult issue. Other than a cost issue, scheduling reserve dramatically exacerbates the manning problem due to FTL limitations (even without additional ASR-Fs, sickness rates, etc caused by schedule disruption)--especially in light of the "old" A day system.
Fr' instance, at an outport with 2 morning flights and 2 evening flights under the 'old' system a person could be asked to cover 4 potential flights on the first day. At best, a reserve duty cuts that in half.
During a typical "A" day under the same circumstance an individual could be asked to cover the 2 evening flights on the 'day of'. This drops to 1 due to the 23-hour FTL limitation (it's doubtful those tagged for reserve would be available to answer the 10-hour notification outside the reserve block even without CC so's it wouldn't happen). In fact it needs even MORE lead time than the old system because the person has to be notified near the beginning of the block, given 10 hours, then report. And this might cause problems where due to the long-haul and schedule reversal the reservist is required to call fatigued under the terms of his license--depending on his personal rest.
If given a positioning flight on a reserve call up to operate from ANOTHER long haul outport, not only must the PT time be considered but also a room booked and 10 hours on top of this. Further reducing the asset availability and increasing costs.
Deploying people to HKG and having them pull reserve there MIGHT reduce some of this, but it also has lodging and allowance costs, FTLs, and duty cycle limitations. Not to mention fatigue issues. Even without the ASR-F factor straight reserve at outports can be horribly inefficient for the company. And fatigue isn't a company issue--it's a CAD and certification issue. The company can't waive the requirement that pilots not fly unfit, nor for AOC, safety, or liability would it sanely want to try.
Bottom line is if we're already short on people scheduling reserves at outports will make it worse.