Should leaders, encourage mistakes on their team?

John Maxwell stated in his book "Failing Forward" that honest mistakes should actually be encouraged, not just tolerated.

William L. McKnight, who served as 3M chairman of the board from 1949 to 1966, encouraged 3M management to "delegate responsibility and encourage men and women to exercise their initiative.". He also mentioned that "Management that is destructively critical when mistakes are made kills initiative. And it's essential that we have many people with initiative if we are to continue to grow."(Source: http://solutions.3m.com/wps/portal/3M/en_WW/History/3M/Company/McKnight-principles )

Planned as it may be, when someone tries out new things failures are likely to happen. Some companies like to talk about giving employees the freedom to make mistakes. Only a few found a way to incorporate possible chance into company policy. Take Google, for example. Google has placed guidelines around employees’ use of their “20% time”. It is the one day a week an employee spends on side projects. Is it a waste of time, learning process or platform for building the next big thing?

I do think that tolerating honest mistakes and giving employees the freedom to explore creates a culture of learning and innovation. I would say that the key to driving innovation is providing a nurturing environment where employees feel encouraged to take risks and make courageous decisions.