I think the topic has been done to death. managing fatigue is an individual issue.
For example mil SAR UK routinely work a 24hr shift pattern. As an example, arrive at work at 07.30, brief/do trivia till 10.00am; then do 2hrs training. 20.00hrs (or dark o'clock) do two hours training. Then at 3.30am next day get a job....
It may not be right (I dont think best practice or customer satisfaction has yet been tried in court) but it is what it is, and when push comes to shove the highest level of service is delivered.
Commutting CC on the basis of fatigue is a non issue in my opinion.
Now to give up cheap flights in favour of striking on the basis of BASSA information, well that has to be a huge issue!