Suckered into the "Flashing Headlights" Gang Initiation eRumor

One of the enduring false eRumors on the Internet warns motorists not to flash their headlights at any oncoming cars driving with their lights off because it may be a member of a gang who, as part of a gang initiation ritual, may follow you and assault or kill you.  Many versions of the eRumor have been falsely attributed to law enforcement agencies, but there have also been numerous instances of members of law enforcement or government agencies passing the warning along to others as though true.

The Royal Canadian Mounted Police (RCMP)
A version of the eRumor came from the Royal Canadian Mounted Police.  It The RCMP later issued a release saying that "One of our Saskatchewan employees sent this e-mail on to others in good faith without realizing it was untrue. The information contained in the e-mail is FALSE and the RCMP regrets any unnecessary alarm this may have caused the public."

Government agencies in Shelby County, Tennessee
According to an article in the Memphis Flyer, the gang initiation eRumor got circulated in 1993 by an employee of the Community Health Agency who said he'd gotten it from the Sheriff's department.

Houston, Texas
The Houston Chronicle reported in September, 1993, that Houston Police and Harris County Sheriff's deputies were put on alert because of rumors of the flashing headlight rumor.  Warnings were reportedly broadcast to officers on several occasions that a local gang might be involved.