An artist named EVERLAST has a cool song called What It's Like. I's basically about walking in other people's shoes.
In a perfect world of honest folks, there would be no CPO involvement in this. Just the Safety folks trying to make adjustments to schedules and policies.
But this is one big fat complicated issue with a really long list of factors, some under the pilot's control, some not.
All it takes is one liar clearly playing the fatigue card, to turn a sympathetic Chief Pilot into a bad cop for the rest of his career.
My personal opinion is the contractual and FAA limitations are completely reasonable from a fatigue standpoint, if the pilot ensures their rest time is actually rest. Throw in screaming babies, commuting, drunk neighbors, whatever and that all changes.
Chronic stress is another story. The "I'm sick of this crap!" kind of stress. Every day, month after month, on reserve, with scheduling owning your nutsack, yanking you around, not abiding by the contract.
That kind of stress can bring a pilot to the breaking point. Next you look for an escape or maybe just a middle finger to the company and play the fatigue card.
Are you fatigued? Maybe not the "not enough sleep" kind, but you are no less fatigued.
The nature of our jobs can produce quite a bit of frustration and chronic stress which can result in fatigue of extremely varying degrees depending on several personal factors ranging from experience, life situation, health, genetics, background, etc etc. Our job does not allow the 'band-of-brothers" teamwork effect to mitigate any of these factors. We are each very much on our own in all this on a day to day basis.
Finally, I would hazard a guess that most valid fatigue calls are not the result of a lack of sleep. More so the variety of Peter Finch yelling "I'm as mad as hell and I'm not gonna take this anymore!"
Mad about what? contract violations, being stuck on reserve, commuting not by choice, getting denied the jumpseat, no chance of upgrade, being downgraded, scheduling yanking you around like Pinochio, repositioning airplanes, endless four day trips, etc. etc.
And yes, it could suck more, (you could be on furlough or fighting towel heads) but everyone has a different breaking point and will cry uncle in a different manner, at a different time. Just don't inappropriately play the fatigue card, just because you're sick of all the crap. (Man up or put on your big girl panties on that one.)
Doing so makes it harder on those who have to make a fatigue call, when they actually are just plain tired.