: It is common knowledge in psychic circles that the astral body
: doesn't leave or at least stays close to the physical body
: of the deceased. The reason is because most people don't
: prepare for their deaths, consequently they don't know what
: to do after their deaths. Not knowing any better, they
: “stick around”.

That is due to getting caught up in the sensory input of the physical world, and avoiding reflection, meditation, and silence of all sensory input. This reduces the communication with the larger self, commonly called God, and therefore leaves one unfamiliar with being bodyless. An out of body experience is close to the experience of death, only the desire to stay fades with the lack of participation.

: In one of his book, Robert Monroe mentioned such a case of a
: man whose physical body was lying on the ground because the
: man died in a battle, yet his astral body tried to animate

: the physical body over and over, not realizing and
: understanding what has happened.

: In many cases people decided they wanted their bodies to be
: cremated. The importance of how crematoriums are built is
: important only if the theory of “catching souls” after
: death is true.

The soul is eternal, and not of the physical world. It gives rise to desire to manifest a physical body, to experience idea, in the physical world. So, a soul cannot be caught. The soul is also everywhere.

: What other easier way exist to catch “souls” then at a
: crematorium?
: The time when the soul is at the body that is getting
: cremated.

: Are there Faraday cages or some kind of electrical/magnetic
: force fields around those chambers where the physical body
: is cremated, to catch the departing “souls”?
: If there is, it certainly won't be advertised; “it is a force
: field to capture “souls” but disguised as some kind of
: safety or protection device.

The ones I have seen and worked on, were just metal furnaces, with minor electrical control wiring, and had small windows, for the relatives to watch the process.

: Either way, it is a prudent act not to stick around the
: expired body.

: “The quest to conquer death is as old as man himself. We
: conjure dark angels, whose untimely arrival we hope to
: avert with guile and perseverance. But in the end it is
: inevitably the grave, not hope, which prevails.”

Here are some pictures of various kinds,

https://www.google.com/search?q=crematorium&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi6qa3jj-zKAhVI1GMKHVCEBqwQ_AUIBygB