There are some exceptions. Some organizations have played April Fool jokes on the public with harmless and hilarious results. Here are my favorites:
The Taco Liberty Bell:
The 1990s brought the days of corporate sponsorship of stadiums and other venues. In 1996 the Taco Bell Corporation sent out press releases and advertisements that they had purchased the Liberty Bell and would rename it the "Taco Liberty Bell." They would allow the bell to remain on display in Philadelphia half the time and would keep it at corporate headquarters the other half. Furious Americans began calling the park where the Liberty Bell is kept, as well as their Senators and Congressmen. Taco Bell immediately revealed that it was a practical joke.
The news even made it to the Presidential press conference that afternoon. Mike McCurry, then White House Press Secretary had a great one-liner for the press. He said that Ford Motors had purchased the Lincoln Memorial and it would be re-named the Ford Lincoln Mercury Memorial.
Burger King played a great joke in 1998. The company took out a full page ad in USA Today. The ad described a new product, "The Left Handed Whopper" designed for left-handed people. The whopper was made by rotating all the ingredients 180 degrees for left-handed customers. Burger King announced the next day the advertisement was a hoax. But for several days, people came in requesting the Left-Handed Whopper. Others requested the old "Right-handed Whopper."
National Public Radio (NPR) is not above a good joke. In 2004, All Things Considered informed us the the US Postal Service was beginning a "portable zip code" policy. Since the FCC had recently allowed customers to keep their telephone numbers when they moved, the post office would allow customers to keep their old zip code numbers. The program stated that the portable zip codes would put Americans in the demographic, not just geographic landscape.
A scientific newsletter, New Mexicans for Science and Reason, published an article in the April edition (1998) that the great state of Alabama was changing the value of Pi. According to the article, the state legislature had returned the definition to the "biblical" value of 3.0 rather than 3.14159. The real purpose of the article was to parody the legislature for its position on the teaching of evolution. News of the article spread quickly and the Alabama legislature was inundated with phone calls.