Mr. Goldberg mentions a "nudist colony." The term "nudist colony" is no longer commonly accepted as a proper term for a nudist environment. It is more accurate to use terms like "nudist camp" or "nudist resort." However, when Mr Goldberg was young, when they were a reasonably new phenomenon, everyone knew them as "nudist colonies."
During the medical examination scene, the characters repeatedly claim they had no clothes on. You can see that they are all still wearing socks. However, socks are not really considered to be "clothes."
During the "stepping" exercises, the instructor is moving her feet "in" on the counts. When the staff follows her, they go "out" on the counts.
Amanda Barrie, as the ballet instructor, takes the dance class in high heels.