They've coded for 10 or 20 years, and now just sit back and design interfaces, write specs, evaluate technologies, mentor juniors, do code review, and of course the ultimate mind blow when you're trying to figure out who to fire: they remove code instead of add it. Unfortunately for the company, these "imposters" do indeed get weeded out in preference to the recent college grad copy/pasting thousands of lines of StackOverflow answers. I usually escape before all that drama though!