The problem is when the other pilot takes out his earpiece and decides to "go to speaker."
Not in my airplane, he doesn't.
As I'm the Commander, rule number one is headsets only, except on very rare occasions, whilst on the ground.
If the others complain, I tell 'em to refer to the Chief Pilot.
As I AM the Chief Pilot, this does no good.
Heaven knows why they do it, but it's very selfish. I wore my hat all the time so as not to disturb anybody.
My opinion exactly.
I have been known for many years to give First Officers maximum leeway with their ops...their sector, their way, but....headsets
only thank you very much.
PS: In nearly forty years, not one F/O has complained.
Not one.