There has been exactly this type of collusion in the past and I would argue it's still ongoing, just better covered up. http://fortune.com/2015/09/03/koh-anti-

There has been exactly this type of collusion in the past and I would argue it's still ongoing, just better covered up. http://fortune.com/2015/09/03/koh-anti-poach-order/ http://fortune.com/2015/09/03/koh-anti-poach-order/