Years ago, two top-40 stations in Washington, DC, WPGC and WRC, both had a "write it down" contest during an Arbitron survey. They would play recordings of a station person going up to someone on the street and asking the person to write which radio station he or she listened to. If they wrote WPGC (or WRC), people in the promo would win money. The stations would end the promo by saying, "If someone asks you to write down which station you listen to, write down WPGC and you could win money." IIRC, this one got flagged by Arbitron.