The documentary description is interesting:
For his second documentary feature, Errol Morris originally set out to chronicle Vernon, FL, because it had the highest rate of a particular sort of insurance fraud -- dismemberment performed for profit -- than any other place in the country.
In the youtube comments for the film, found this:
Vernon is a surname, from a masculine name that is derived from the Gaul word vern for Alder tree (also springlike, flourishing, or full of life) and a Gaulish-Latin suffix indicating a location. Thus Vernon is a "place of alders". Variants include Vern, Vernard, Verne, Verna, Sberna, Sberno.