Dick York's absence as Darrin from Samantha Twitches for UNICEF (1969) is explained as going on a business trip to Chicago. He is also mentioned at the end of the show as having returned from the trip, but is not seen. Dick York's medical condition resulted in his character's omission from some of the final season five shows.
All the cars in the parking lot scene are Chevrolets. That's because Chevrolet was a major sponsor of the show at this time. The cars are all backed into their spaces in order to display the grill with the Chevrolet "bowtie" emblem. That's because even back then cars from the same major manufacturer (GM) all tended to look the same.
The title refers to The United Nations Children's Fund (or UNICEF) which was created in 1946, to provide emergency food and health care to children and provide long-term humanitarian and developmental assistance to children and mothers in developing countries.
Herb Voland and Sharon Vaughn had appeared together earlier that season in Instant Courtesy (1968), but playing different characters.