My 2c.
Unable - means (you are) unable to comply for an operational reason (with the instruction / clearance). I am not going to question what the nature of your operational requirement is - not on the frequency anyway. A phone call after shutdown might be requested however.
Bottom line: if you operationally require it you get it.
But if you are simply being operationally 'expedient' and you don't 'really' require it, than instead just request it.
Unable means unable - not unwilling!
Last edited by one25six; 30th Dec 2005 at 13:10.