The new technology uses radio waves that are detected and reflected back to the casino's electronics. A magnet would have little or no effect on this process. Neither would shielding the chips with "lead pockets" as there's no particle radiation invloved. However, anything that is opaque to radio waves would probably work. No help on the tables, but lining your pockets with aluminum or copper foil would probably work if you don't want to be detected leaving the casino with some of their gaming equipment.