Part of this goes back to documents and work uncovered in the Jobs book and before, in which executives from companies made informal agreements to not go after other employees.
And yet, Intel actually had a written document describing a non-poach agreement with Pixar, where Intel's policy was to not hire any Pixar employee without the Pixar CEO's express approval.
Steve Jobs personally emailed Eric Schmidt to ask Google to stop poaching an Apple engineer, and Google responded by arranging to immediately and publicly fire the employee who initiated the call.
Google's director of staffing Arnnon Geshuri revealed the existence of a formal Do Not Call list in an email to Eric Schmidt, such as the ones that the Justice Department claimed in the original 2010 settlement.
Pixar and Lucasfilm explicitly agreed not to "get into bidding wars" for employees, as did two senior SVPs at Google. The latter two reportedly agreed to do so by restricting recruiting practices, and sent copies of their idea to Google CEO Eric Schmidt and Bill Campbell, on the boards of Intuit and Apple.
Numerous companies are named in this plan to keep employees locked into one company or to prevent bidding wars for employees, fixing employee costs