The Metallic Metals Act of 1947

"In March 1947, Sam Gill, research director of the Sherman & Marquette ad agency...asked subjects... what was their opinion of the Metallic Metals Act?  He reported that 70 percent of those surveyed readily offered an opinion.  Of this group, 58.6% favored leaving the Act to individual states; 21.4% thought it would be a good U.S. move; 15.7% thought it shouldn't be required and 4.3% thought it had no value at all.

"The curious part of this finding was that the Metallic Metals Act didn't exist.  It was an entirely fictitious piece of legislation.  But many people apparently had an opinion about it nevertheless.  Gill suggested the response to his survey demonstrated that 'the average U.S. "man on the street", while not the world's worst liar is always willing to give an "opinion" on any subject whether he knows anything about it or not.'"

From Electrified Sheep by Alex Boese.  In 1978, some researchers tried to find Gill's original research data and could not; therefore, it is possible he made the whole thing up.  Nevertheless, it's a fun story, and since we're always trying to profit from the sometimes bizarre behavior of humans, it makes for good summer reading.