C C in the cockpit to save the day, my thoughts...
With only 1 pilot in the cockpit and a C C member to save the day, what hope would they have if the remaining pilot at the controls of an airbus did the following. Over a 10s period turn off the primary and secondary flight controls and then the engine masters. At this point the C C gets startled by events and wouldn't know what to do while the pilot decides to get out of the seat to deadbolt the door while attacking the C C member. All would be lost, it really is a pointless exercise.
I would prefer to trust the other pilot being left in the seat alone rather than a brand new C C member with no psychometric evaluation or particular in depth personal or professional history being known.
How about 2 pilots in the cockpit and while on controlled rest the "on duty" pilot choses to Jettison fuel while over the ocean or polar route.
To me, the safest answer would be to ensure that there is a temporary way to disarm the door locking mechanism. When there is only 1 pilot in the cockpit the deadbolt would be powered open and the door access gained . Aircraft with coded door access would mean pilots would need to have a personal code created for them "alone" should they ever need to use it as above. Could a potential terrorist get the code off you? Well when you go out to the bathroom, would you want to open the door for them and suffer the same fate either way with them at the controls?
Perhaps in the thread title incident it was a case where the pilot is at the controls and the C C member becomes incapacitated blocking the door. Now you will have no one at the controls while the pilot attends to them and removes them from the blocked door area. No pilot at the controls caused by a worthless policy which is described above as pointless.
Just a few thoughts there, not the best solutions but better than the current policy.
Enjoy your week all
Jack