Actually this could work. Defcon this year was at Caesar's palace and despite a voting machine, a couple cars, multiple IoT devices, an electric scooter, and the Beijing Noodle's menu being pwned, nobody managed (dared?) to fuck with any one of the thousands of electronic slot machines.
People do do that; this is pretty well known. But they tend to view it more in the vein of "trade secrets" than "I'm going to demo this to everyone for free".
Actually this could work. Defcon this year was at Caesar's palace and despite a voting machine, a couple cars, multiple IoT devices, an electric scooter, and the Beijing Noodle's menu being pwned, nobody managed (dared?) to fuck with any one of the thousands of electronic slot machines.