Death is Like a Happy Balloon (1973)

Death is Like a Happy Balloon by Dr Cassandra Henge was one in series of books published by Bullyrag Books who specialised in introducing children to alarming topics without alleviating any of their readers' fears. Other books in the series included Totalitarianism is Like a Merry Smile, Slaughterhouses are Like a Paddling Pool and Organ Failure is Like Fudge.

Death is Like a Happy Balloon contained a subliminal trigger word, as is used in hypnosis and psychological conditioning. The idea was that if there were any future social problems - overpopulation, revolution, widespead idiocy, a disproportionate number of old people - the government could use the trigger word and cull a whole generation by activating overwhelming suicidal thoughts.

The state carefully chose the word (a neologism, unrepeatable here for legal reasons), so that it would not trigger an unintended suicide epidemic.

In 1975, however, a UN human rights inspector was sent to the UK to interview alleged victims of state brutality. His foreign name by chance matched the trigger word and thousands took their lives following a television broadcast about his visit.
It was later revealed that the government had specifically requested the inspector by name. Additionally, it had total control over the broadcast's contents and when it was aired to ensure that it reached the maximum number of viewers.