(1969) Governor John Love of Colorado with trick-or-treaters collecting donations for UNICEF.
The practice of fundraising for the United Nations Children's Fund (UNICEF) while trick or treating dates back to 1950. According to UNICEF, US trick-or-treaters have raised over $160 million for the fund to date.
Source: UNICEF
(1983) A shot from a PSA filmed by Dr. Joyce Brothers, a psychologist and TV personality, on behalf of the National Confectioners Association, which sought to calm parents after the Chicago Tylenol Murders.
Tylenol capsules were laced with deadly potassium cyanide in the Chicago area in September 1982. Seven people died, and the murderers were never found. The ordeal raised concerns for parents, who worried about their children accepting candy from strangers while trick-or-treating on Halloween.
Sources: Business Insider, AP, Mental Floss
(1983) The 10th annual Greenwich Village Halloween Parade in New York City.