There are always some cultural, social and religious backgrounds that block us from having OOBE. Tom Campbell also stresses about the fact that having OOBE is a personal experience that doesn't need others tools and techniques to be done. We don't have the same experiences and don't have OBE's the same way. We don't need to see our physical body, it happens but not all the time. As consciousness we are more open and free than only physical beings. The physical body is only virtual. Very interesting video where he also talks about the" differences"between OOBE and Lucid dreaming and dreaming... etc It is related to our ways to consider these things. So if you think that there is a difference between them, you put burdens and limitations in yourself. When you stay open your consciousness expands.