Did not allow Uri Geller to cheat on his show.
When Uri Geller was invited to perform on the Tonight Show, Johnny Carson got advice from James Randi on how to keep Geller from cheating. Randi told Carson to ensure Geller was not allowed to handle the spoons and other objects set out for him to "bend with his mind".
Needless to say, without weakening the spoons by repeatedly bending them prior to the show, Geller was not able to bend them by simply grabbing the end of the spoon, gently waving it, and then telling the crowd that he used his mind to mend it.
It was only a temporary setback for Geller as he went on to fool other chumps.
https://groovyhistory.com/amazing-randi-uri-geller-tonight-show