I must say this is one of the best lines I have read in a long time and such a forgotten trait of an experienced manager looking for the best people.  Take a look at this: Before Selling Candidates on the Job Sell them out of the Job.  Bottom line - I love it.  Professionally it has been a method employed in my own tool box for over a decade and it works more so than any other when determining the true reasons and drive behind a candidate's move or decision to make a change.  Managers are so interested in making their job attractive (which is important) that they forget to uncover all of the nit and grit about a person.  They run into the interview looking to please, rather than looking for all the reasons why it might not work out.  Best thing a manager ever did was talk someone out a position.  You know if they could do it during the interview, how long would it take for someone else to come along and steal them from your position?  Selling against your job during the hiring process increases the average length and tenure of professionals in their roles as it peers into the bottom line reasons why someone would want to work for a company.

The Hiring Site through CareerBuilder discusses the subject and a book called Hire on a Whim most recently on their blog page.  Though all of the reasons and discussions I would not turn to as best hire practices, the art of selling people away from a job is critical.  And it is equally important to know when and when not to do this.  Timing is the key and essential ingredient when figuring out the best time to employ the method.  Doing it to early will give the candidate a bad taste for the manager, making them believe they have no faith in the company or the manager is simply a poor executive.  Do it too late and the "WOW" of the role might already be set it and you could not pry the person away no matter what was said.  The key is right after the person believes he/she is the person the company wants.  When that moment comes, then begin the process of asking them "WHY" and explaining to them all the reasons why this role is challenging and people typically shy away from challenge.

I get the question - why would you want scare the candidate away.  Simply put, you are not.  You are only scaring away the people that will leave the role after shortly joining when they find out all the nuances of the job.  If you can "unsell" the job and the candidate still has strong interest despite the obstacles - you have a winner.  An interested and now "educated" party on the position that understands the culture, obstacles, and points of resistance before taking the position can anticipate the role and their integration into the new environment.  With that mindset coming in, surprises are less impactful and professionals are prepared to attack all sort of issues with creative solutions overcoming what others would deem impossible.  Managers need to understand that the best candidate is not always the most motivated or emotionally tough candidate, characteristics needed in the right hire.  Take some time to turn them off from the job, and you will be amazed at all of the benefits (less turnover, happier culture, etc.)