Continuity mistake: When Ellen is dancing for Clark, she slides down against the door. There is pink toilet paper by her feet which disappears.
Continuity mistake: This is the only movie in the Vacation series where the Griswold name is spelled "Griswald." This is shown on the beginning credits on Clark's passport as well as family name on Pig in Poke game show.
Audio problem: When the camera thief tells the Griswolds to take their shoes off and get in the fountain, Ellen is heard reacting to the cold water, but she hasn't even gotten in yet.
Audio problem: When the family is atop the Eiffel Tower and Rusty is flirting with a woman, a dog barks but it doesn't make a bark motion. When we see it bark a second time it actually is barking.
Factual error: The supercharged "Honda 750" motorcycle is actually a Honda Rebel 250.
Other mistake: After the Griswolds leave the German couple's house, the man says "Who the hell were they?", and the woman says "Beats the shit out of me." However, since they slept there overnight, they had enough time to discuss it in private much earlier.
Answer: The answer could be any of those suggestions. It could also very well be a movie mistake. It's not uncommon for character names to be misspelled, either on some document or in the cast credits.
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