One of my missions was to drop Chieu Hoi leaflets. We called the leaflets, “safe conduct passes.” I remember the Chieu Hoi leaflets were delivered to me, at the airport in packages of about 300 to 500 leaflets. The mission was to fly over suspected Viet Cong areas and drop the leaflets a few at a time, out the window of the airplane... I remember dropping Chieu Hoi leaflets a few at a time and becoming frustrated by the task. Consequently, I also remember throwing the whole package out at once! I never remember ANY Viet Cong bringing in a Chieu Hoi leaflet, and surrendering. Looking back, I think the leaflet was printed on thin paper, which would deteriorate quickly because of the rain.
The following was reprinted from Wikiipedia
Defection was urged by means of a propaganda campaign, usually leaflets delivered by an artillery shell or dropped over enemy-controlled areas by aircraft, or messages broadcast over areas of South Vietnam. A number of incentives were offered to those who chose to cooperate, along with psychological warfare to break enemy morale
By 1967, approximately 75,000 defections had been recorded, but analysts speculate that less than 25% of those were genuine. The program had some difficulty catching on, due in part to culture gap—errors, such as misspellings and unintentionally offensive statements.
Overall, however, the Chieu Hoi program was considered successful. Those who surrendered were known as "Hoi Chanh.”