My 2c as an ACN alumni... the author's conclusion could as such be extended to the entire consulting industry. There are three reasons this does not hold though:

- consultants are bound by strict NDAs

- the client hires me because of my experience in the field (which includes competitors) and needs to live with the fact that I'll carry that experience with me

- if the client didn't want me to carry my experience with me from their project, he'd need to pay me for the rest of my days for just doing nothing