Hi Giuseppe,
I like your humour when you say "it is part of the game" :). I really laughed in myself for some minutes.
To be a little more seriuos, Cisco's vested interests are that there are many well educated and productive engineers around the world who are able to design, implement and troubleshoot Cisco networks on large scale.
Books containing lots of errors make it more difficult to grasp and digest Cisco networking technology that itself is becoming more and more sophisticated year-by-year, as new features and technologies arise.
This in effect slows down quick application of new features and also the influx of new generation into networking, both causing present and future business loss to Cisco that cannot even be estimated.
So, from Cisco's point of view I don't think it's a very funny game and I would encourage Cisco and Ciscopress to produce clear, easily readable and understandable study materials if they want to be successful in long term.
And I'm saying this because our personal long term success (I hope I can say our) is also tied to the long term business success of Cisco in general.
Cheers:
Istvan
