Sounds interesting. I'm going to have to try to research this more, if nothing more than curiosity.

My guess as to it's illegality would be that if it allows you to see auras and *truly* into the "astral plane" then you would be able to see the fallen angels or demons who inhabit that relm. An ability I don't believe Satan would be too keen on the general pubic having access to. I don't believe God's unfallen heavenly angels would be inhabitants .. though perhaps they're able to interact there if/when required.

Stephen King wrote a book called "Insomnia" Basically, older people became insomniacs, and start to see peoples life force. My admiration for King has gone away...but I find his writings more and more curious. Wonder what he knows...