A few of the managers we spoke with for this book worried that the tour of duty framework might give employees "permission" to leave. But permission is not yours to give or to withhold, and believing you have that power is simply a self-deception that leads to a dishonest relationship with your employees. Employees don't need your permission to switch companies, and if you try to assert that right, they'll simply make their move behind your back.

The Alliance: Managing Talent in the Networked Age