Deliberate mistake: Obviously due to the family nature of the film, but when Peter stabs the White Witch's henchmen at battle, the sword always remains clean, and never bloody. (This is a Disney family film and as such no blood is shown. Still a mistake, but there's the reason). (01:56:10)
Deliberate mistake: Mr. Medulla said that Will stepped on his foot when he was walking to his desk. If you look closely you can notice that he stepped over his foot instead of on it.
Deliberate mistake: Charlie's room has a hole big enough for him to climb out of in the ceiling. I know it is to show just how poor the family is, but we see he has only a thin wool blanket for warmth. He would have frozen to death in his sleep during winter by now.
Deliberate mistake: In the end of the NASCAR race, Tripp and Gordon get into a crash making Gordon spin, but he somehow is still able to come in second place even though every other racer was right on his back when he spun. He wouldn't have been able to regain that much speed in that short amount of time.
Deliberate mistake: During the dance number in the Dead Bar, the blue pirate has a sword stuck through him with the handle in the front, later it changes to the back, then to the front again. Seen when the groom falls back and grabs the handle, then picks the pirate up and drops him. (00:19:15 - 00:20:05)
Deliberate mistake: As the horse named "Sir Trenton", who is supposed to be a stallion, is galloping away you can see that "he" is a female.
Deliberate mistake: The turn count for Lisa's stay in the Cryogenic Sleep Chamber is off. The card reads she should be there for 5 turns. 'Turn' can either represent a single move made by either Danny or Walter, or a complete game cycle where both Danny and Walter have made a move. If we count the turns by player, it comes to 8 and she's awake 2 turns too late as it should have happened at the start of 6th. If we count both players' moves together as a start of a turn, then she's awake 2 turns too early as its turn 4 and not turn 6. It seems obvious from showing us the shower suddenly start up that this is the correct point in the film they wanted her awake, so it's unlikely she was actually awake off-camera during the Astronaut's arrival and we just didn't see.
Deliberate mistake: Frank Beardsley moves his family into an old, defunct lighthouse, and subsequently makes a project of restoring the rotating lamp and actually running it. But lighthouses are navigational devices. Each one in use has its own unique, catalogued period, which identifies it and therefore helps a distant ship determine its own position. By running a "phantom" lighthouse, Frank, a career Coast Guard officer, risks confusing ships' navigators at sea. No real nautical officer would do such a thing.
Deliberate mistake: There was a black wrought iron fence behind Whitney but with enough space for JD to drive between them. After JD parked, Whitney (and her friend) were much closer to the fence, but they were also at the rear of JD's parked SUV, which would not be spatially possible. When JD, Jane, and Ally got out of the SUV, they walked right in front of Whitney, who was now much closer, and the fence was no longer behind Whitney. (00:27:50 - 00:28:14)