Deliberate mistake: After Peter says, "We can't both have her lady," he shuts the window from the outside and the bottom pane is placed on the outside of the top stained glass pane. This is obviously done specifically for this shot so Peter would be able to shut the window and try to keep the Darlings from opening it. However, in the next shot as the Darlings succeed in opening the 'stuck' window, the bottom pane is on the inside of the top stained glass pane. (00:02:05 - 00:58:45)
Deliberate mistake: Whenever O.J. the owl is flying, there is the sound of wings flapping that sounds almost like a chicken flapping its wings. The flight of an owl is almost silent.
Deliberate mistake: When Harry is seen stepping outside of his hotel the evening after he arrives in Paris, behind him is the familiar Eiffel Tower gloriously illuminated against the night sky. Frequent Paris visitors or residents might recognise the hotel as the Plaza Athenee - to see the Eiffel Tower from there you'd need to be looking in the opposite direction from what we're shown.
Deliberate mistake: When the blue car backs up and pushes Tom and Sarah's compact over the cliff, in the close-up the woman is seen, but in the next shot it is very obviously not that woman driving away. (00:47:50)
Deliberate mistake: Near the end of the movie, in the Yankee Stadium scene, Adam Sandler sneaks onto the field. He then assaults a police officer and announcer who try to stop him. Rudolph Giuliani condones, even encourages Sandler's behavior. Giuliani acted entirely out of character, as he has an extensive history of being staunchly anti-petty crime and pro-police officer. (01:27:15)
Deliberate mistake: In the scene where Bob and Charlotte first glance at each other in the elevator, the film has been reversed. 3 mistakes are visible. The first one is that the woman's Kimono is reversed, left side tucked into the right. All Japanese garments are always tucked in right side first. Only on the day of your funeral is the left side tucked in first. The second mistake is the lapel hole on Bob's jacket; it is shown on his right. The lapel hole is almost always on the left side of a men's suit or sport jacket. And in every other scene in the film, his lapel hole is on his left. The third is the birthmark by the ear and the 1 inch vertical scar on Bill Murray's cheek are shown on his right side. When in actuality, they are on the left side of his face. (00:08:00 - 00:08:35)