Hi Searching.
Well, here's my point of view.
When you get out of your body, it's not your spirit that moves out of your body, it's the point of view of your consciousness, and it doesn't go out of your body leaving it empty, but the subtle energy expands and your point of consciousness moves out of your body. So nothing is left 'open' or 'alone', because your essence, your spirit, which is more than your body and not subject to spacetime, continues to include your physical body in its sphere of existence. This is why we bilocate, or experience what Robert calls the mind-split- having the experience of splitting conscious awareness into two, and serializing the experience when we reintegrate with our body.
It's like when we sleep, our consciousness is not in the physical experience of being in the physical, but attenuated leaving the subconscious to experience the nonphysical or astral without judgement.
The energy body is more of a field than a carapace, it has no doors that open and close, and nothing 'enters' or 'exits'- we project our consciousness out of the realm of the physical to the realm of the nonphysical (astral, mental, etc.)

In the years of being in this forum, I have never heard of a person getting into negative entity problems because of projection- however, I personally have used projection to help in that regard.