The symbol became widely known in civilian life in the 1970s. It was the central theme of the popular song "Tie a Yellow Ribbon 'Round the Old Oak Tree", performed by Tony Orlando and Dawn, as the sign a released convict requested from his wife or lover, to indicate that she still wanted him and that he would therefore be welcome to return home. He would be able to see it from the bus driving by their house, and would stay on the bus in the absence of the ribbon. He turned out to be very welcome: there were a hundred yellow ribbons.
From the Library of Congress:
In October of 1971, newspaper columnist Pete Hamill wrote a piece for the New York Post called "Going Home." In it, college students on a bus trip to the beaches of Fort Lauderdale make friends with an ex-convict who is watching for a yellow handkerchief on a roadside oak. Hamill claimed to have heard this story in oral tradition.
In June of 1972, nine months later, Reader's Digest reprinted "Going Home." Also in June 1972, ABC-TV aired a dramatized version of it in which James Earl Jones played the role of the returning ex-con. A month-and-a-half after that, Irwin Levine and L. Russell Brown registered for copyright a song they called "Tie a Yellow Ribbon Round the Ole Oak Tree." The authors said they heard the story while serving in the military. Pete Hamill was not convinced and filed suit for infringement.
One factor that may have influenced Hamill's decision to do so was that, in May 1973, "Tie A Yellow Ribbon" sold 3 million records in three weeks. When the dust settled, BMI calculated that radio stations had played it 3 million times--that's seventeen continuous years of airplay. Hammill dropped his suit after folklorists working for Levine and Brown turned up archival versions of the story that had been collected before "Going Home" had been written.