3D printing for good and evil

Any technology can be used for good as well as evil. A hammer can be used to kill a person, or build a home for one. This same duality goes for the emergent 3D printing technologies, and the full potential of this revolution has not yet been realized. In this video from 16×9, the different sides of the 3D printing revolution is investigated and both constructive and destructive uses are covered. The power of this technology is tremendous, which could make it a dangerous tool if it is used by bad people. What is your opinion and thoughts on this subject?