"Rumors flew at the time that Hughes bought the Silver Slipper casino because he feared a camera was placed inside the toe of the shoe, which always stopped and faced his Desert Inn penthouse. After the casino’s previous owners refused his repeated requests to turn off the shoe, Hughes bought it in 1968."

http://www.lasvegassun.com/news/2009/nov/06/las-vegas-boulevard-sign-lighting-ceremony-set-mon/