Corman elected to film the movie on location (in Southern Missouri) and some of the local elders were less than hospitable when they learned about the subject matter of the screenplay. Thereafter, the movie makers decided for the safety of the cast and crew to keep some of the townsfolk used as extras in the dark as to what the movie was really about.
If you look closely, the playground scenes were actually filmed in three different park locations (the playground equipment varies in size and shape depending upon where the footage was shot). The change of locations was necessitated by the fear of the film makers that they were about to be run out of town by mobs of irate segregationists.
When the film flopped, Corman tried to recoup some money by reissuing the film as an exploitation picture under the title "I Hate Your Guts."