Mediums are few in number that are real, but there are a few. Even they lie about the afterlife some willingly, some without knowledge but ALL tell lies. The bible is the sole proprietor of fact and truth concerning the afterlife. The desire of man to know about things of the beyond is not the problem but the ways and means of gaining that knowledge present the issue of false ideas masquerading as truth.
Its an interesting theory if nothing else, but there may be many other such explanations for Ghost-like evidence besides that which is often explained as truth, when it is in fact a lie from hell! The Bible is very clear that human spirits with or without God DO NOT STICK AROUND AFTER DEATH but are rather taken to their ETERNAL REWARDS accordingly!
You will notice that the transition from death to new life is almost non-existent, it is immediate after leaving the physical body that you are present with Jesus. No haunting, no wandering, no unknown.......funny most ghost hunters don't just read the B.I.B.L.E. Basic Instructions Before Leaving Earth?