I've posted this story before ... somewhere ...
Many years ago, I was involved in a business run by my cousin the witch. The usual astrology / crystal / numerology / seance / tarot effluvium.
We were at a "New Age" con(vention), and I was wandering around when a woman came up and asked me to stop "drawing off the energy" of her partner. The guy was doing cold readings and having a tough time, so he blamed me.
At this point, I had an idea (I love spoofing spoofers). I took out this little "bug" transmitter I had been working on, disconnected the battery, and said, "There, that should do it!" She came back a little later and told me that everything was fine, and could I explain the device?
"It's a dampening field generator. See this silver can? It holds a quartz crystal fragment of the highest quality, and these other pieces energize the crystal and cause it to resonate at its prime energy mode. The field can be detected from 50 yards away. I've disconnected the battery, so now it's just an ordinary unenergized crystal."
(I did not tell her that I used it to jam FM radio broadcasts just for fun. The battery was completely drained, anyway.)
Next thing I know, I'm taking orders for my "Psychic Cloaking Device" and making enough money to pay the rent that month.
A few years later, I ran into one of my customers and asked him how well it was working. He gave me a glowing testimonial of how his life changed because dark forces could no longer find him, and blah blah blah ...
"How often do you change the battery?" I asked.
"Battery ... ? What battery?"
Some things are just too easy; like making money selling worthless trinkets to wooists.