I second much said on this thread. & yes I also caution too as I did myself venture into dabbling with astral stuff. Unfortunately my logic at the time was, if some if it is correct especially a majority of the information, then maybe all of it is correct. That is just not the case with much of the astral stuff as they deliberately mix truth with falsehood. One encounter almost shook completely my idea that anything beyond this world existed... & I was confused & in agony for about a period of maybe 2 months. Luckily, whatever guardians or whatnot I had arranged that I had my only "lucid" dream ever where they were very clear with me about where to proceed & to not succumb to losing complete faith in everything.
So when you cite this article.. & everyone posts their warnings I can say as a person who almost completely fell off the path due to this that yes it is a very real danger. I was very spiritual as a child & that one horrible incident shook me to the core.
Anyways! That's the past but eep.. it is very interesting to see how many books at the bookstore are not spiritual but rather more like a curiosity.
I will also mention my encounters with this "astral" stuff was at an all-time high when I was dabbling in it. Since then I have packed up my tarot cards & such. I still am curious but I am definitely wary of any channelings or such. & I am starting to learn how to use kinesiology now to verify certain things.
& I will also post as a personal experience that when I had my first more spiritual experience I didn't know how to contextualize it & incorrectly concluded that it was "me" that had become better & more enlightened & that made me vulnerable to spiritual pride. Hah. I am very glad now that I've learned since. Anyways I thought I'd share from a more personal perspective to verify what is being written here.