Pixel42
Schrödinger's cat
The whole "hot reading" thing is over-blown and I would suggest no one could practically use it to conduct a reading. The time to research it alone would make it financially impractical.
One commonly used trick is planting people in the audience who get information by striking up conversations before the performance (I'm hoping to hear from my late husband, how about you). Another I heard about from a tell all book was a guy who kept all the letters he got from fans asking for messages from deceased loved ones, and then sent free tickets to those who lived in the towns where he was doing his shows. It really isn't difficult to gather information about the sort of people who are gullible enough to go to such shows.