Conditions for 6 Thinking Hats. Assumptions
Having just completed the De Bono 6 hats course, I can honestly say it is a good tool if administered, not only in a mature organizational environment, but crucially, an environment where there is TRUST amongst colleagues as well as trust between managers and subordinates.
One should be able to feel free to share and discuss ideas even if those ideas touch on some sensitive issues.
Otherwise, meetings become a minefield littered with the self-serving agenda's of those in power and casualties of those who took the risk of putting themselves out there.