Well, I do take things in the astral a bit similar like in the material - as in the material I have lots of experience. I find a basic level of politeness and respect for privacy important. If people I do not know really, really well, would sneak into my room while I sleep and stand over me, I would not appreciate that. Same for astral visitors.
Our spirit guides know how to not appear as a astral person, they are there for us anyway, even when one does not see them at all. They do take a suitable appearance for the individual person and situation - so most likely it is not a spirit guide, if you get scared by him/her while you are in bed.

In the wider perspective, even being killed in a horrible death is a learning experience (been there, done that ), but there are sure more desirable learning experiences available. So inside my home I want only family and friends. The nasties and fights I can always meet outside anyway.

As I just did read about the "dreaming for Gaia". Many people do send energy to earth, as they think earth needs all the help one can give her. That made me wonder about tapping earth energy for ones shields...