They list on the trivia that Cary can be heard accidentally calling Mr. Smith his real name, Skippy, in one scene. If anyone knows which scene this is, please let me know. I have seen this movie about 50 times and have never heard it.
I have a feeling that someone jumped to a hasty conclusion when they both call the dog "Smitty".
The scene referred to is when the husband is visiting the wife to apologize for his causing a scene during her recital performance earlier in the day, when the music instructor, Armand, is hiding out in the next room. When the husband (Grant) knocks on the door, the dog barks loudly and runs to the door. As the door id opened to reviel Grant's character, Grant supposedly bends over and says "hey, skippy!" However, what he was actually saying was "Hey, Smitty!" A comment he repeats in paraphrase a couple of minutes later when Grant and Mr. Smith are playing hide and seek.
I have independently verified this by listening to. Oth sections numerous times, and I hear 'smitty' every time, although it's easy to hear the first one as "skippy" due to the dog barking and poor sound, relatively, of the time.