I used to live in Nashville, which is very near The Bell Witch cave.
One of the girls at work opened up and told us about taking a rock from the caves. The driveway you have to exit, she described a a circluar kind of U shape - easy in and easy out for tourists.
She and her friends drove around and around and didn't see an exit. They took the rock back, and lo and behold - they were able to see the exit and they left in a hurry.
One psychic I interviewed there spoke of how many rocks, pepples, sticks, etc are sent back in the mail to the Bell Witch caves as "things happen" to people. They get scared and send back whatever they took.
I had "friends" who wanted to come for Fan Fair and they were going to stay with me. They told me they wanted to take a rock from the caves and place it in my apartment and see if anything happened.
Love them dearly - but I am thankful they never made it while I was there........