A crewmember should be rested for their ensuing FDP. It should not be open to any ambiguity - with the FDP being the basis of a person operating in an aircraft as a member of its crew... 'n' all.
Specifically resting for prescribed sector lengths has a great deal of irresponsibility attched to it. I certainly wouldn't expect it from someone who prides themself on good airmanship.
In respect of 'Brit Nigel', I suspect mature, 'urbane' reasoning was clouded by opportunism and selfishness, not uncommon traits!
BT! - I wonder if you can recall someone who's the very anthesis of a man working up to his limits?! He could certainly provide you with a different slant on what consitutes 'unforseen' in the use of discression
