I did hear Bruce in an interview mention something about if any staff member is fatigued it's their responsibility to report to their manager so they can be relieved of duty.
I'm not too sure what the workplace laws are in Thailand, I'm sure they're not as strong as Australia. But I could just imagine the apprehension of a Thai flight attendant reporting they are too fatigued to work and the subsequent fear they might have of being relieved of their employment.