I'm only describing the convention used most frequently in broadcast long-form narrative comedies I've script edited, written on, or written. (Although in fairness I only can think of three episodes where there's been this kind of misdirect.)
Dave, I always advise people to treat the script readers as your audience - the most important audience members you'll ever have. The script should draw them into the world.
[quote name="Lazzard" post="1084115" date="12th August 2014, 5:44 PM BST"]Not a part of the process I recognise, I'm afraid.
And I'm happy to say it's a part I do.