There seem to be three (at least) Missional Myths that people are embracing to one degree or another these days. They are all born out of solid ideas, but taken to extremes they are detrimental. And the more people buy into these myths the worse it is for their impact on the mission.
In my younger days I ran into an approach to witnessing that combined a good idea (live as you believe, be authentic) with a cop-out. It went something like this: “I let my life be my witness.” These people would really have you believe that a religious lifestyle alone would bring people to a saving faith in Jesus Christ. In fact, they were usually simply too ashamed of their own faith to talk about it.
These days there is a similar, just as pervasive, philosophy in missions. It also takes a good or at least needed idea (sometimes you have to be something other than a religious professional to gain access to the lost) and tries to make it a universal “best practice” for all mission efforts. They would have you believe that the best way to reach people with the story of Christ is to pretend to be something other than a witness.
Now, there are places in the world where Christians are not free to share their story. There are places where people are not allowed to live if sharing the Gospel is their job. In those places, people need another reason to be there. Most of the time their other reason is a legitimate job. However, to convince me that this is the best approach everywhere they need to do more than just say it is so. The data tends to argue against them. Even in places where being a witness is illegal, the people who openly do so see more results than those who hide their faith.
The sad truth is that a lot of these believers spend more energy and time maintaining a “cover” than they do witnessing, all to maintain a method of witness that is less effective. Part of the appeal may lie in the romantic idea of having a cover. Missional types are more susceptible to hero complexes than those who do not follow a missional vocation, and the 007 approach to mission certainly feels more heroic than openly embracing a message and a lifestyle than tend to be looked upon with disdain.