Other mistake: Ferris wants to skip school and who can blame him? In the boring lesson early in the movie, supposedly at the start of the day, look at the student's watches. They all read 6.25. (00:11:10)
Visible crew/equipment: After Ferris picks up Sloane from the school and they leave the parking lot, there is a shot from behind the car as they drive away and Cameron emerges from his hiding place. The following vehicle and the camera boom are visible in the reflection on the car's trunk. (00:31:15)
Visible crew/equipment: When Jeanie pulls up to the field in her car and she says "I hate him." You can see the reflection of the boom mic and the camera in her slightly rolled up window. (00:50:30)
Continuity mistake: The dash or speedometer of the Ferrari is visible multiple times, but two different dashes are seen. In one the speedometer has a top speed of 160 (garage men speeding down the road, when Cameron sees the mileage is too high, and when Cameron sees the miles aren't coming off). In the other it has a top speed of 120 (when they get in the car to leave the garage, and looking over Ferris' shoulder at Cameron leaning on the car in the garage before he kicks it [open matte version]). The two dashes also use a different font for the numbers. (00:55:00 - 01:09:40)
Visible crew/equipment: Near the beginning of the movie there is a brief scene around the empty house. While the camera is in the kitchen you can see a reflection of one of the set guys moving in the fridge handle.
Continuity mistake: The rear view mirror disappears when Jeanie is speeding home.
Visible crew/equipment: When Ferris, Sloan, and Cameron pick up the Ferrari at the parking garage you can see the camera and its reflection in the window directly behind Ferris and Cameron.
Continuity mistake: When Jeanie meets the boy at the police station, his hair changes after every cut from her to him.
Continuity mistake: In the scene where Ferris' mom comes home to check on him to make sure he's really home sick, when she's walking down the hall to enter his room you can see the door knob is a gold/old looking one. When she goes to turn the knob and go into the room, they zoom in on it and it's a crystal door knob.
Visible crew/equipment: When Ferris and gang are driving into the city (Chicago), you hear a song being played and they show an aerial view of Chicago. When they do a flyby of one of the buildings, you can clearly see the helicopter and the cameraman that is doing the filming, in the reflection of the building's windows.
Continuity mistake: Cameron kicks and shatters the glass light on the front of the Ferrari towards the end of the movie. A shot of the entire garage is then shown and there is no glass on the floor.
Continuity mistake: When Ferris is talking with Cameron on the phone and playing on the computer, there is no Pepsi can on his desk. A second later one appears next to his hand. The can then disappears in the next shot.
Other mistake: In the scene where Cameron is sinking in the pool you can clearly see some kind of weight belt or something around his waist, which isn't there when he is out of the pool.
Continuity mistake: When Mr. Rooney goes to Ferris's house he is wearing a long sleeved shirt and coat jacket. A shot of his arm ringing the doorbell shows a bare arm with dark hair. When they return back to a shot of Mr. Rooney, his sleeve is touching his wrist and he does not have dark hair on the back of his hand.
Continuity mistake: When driving home from the city there is obviously a fake backdrop to simulate a moving car. The car can be seen to change lanes but Ferris never actually turns the wheel of the car.
Continuity mistake: When the Ferrari goes through the window and the three of them are standing there, you can see the camera tape on the floor where they are supposed to stand. Also the broken glass on the window changes a bit over the course of that scene.
Continuity mistake: At the end, Jeanie slams the kitchen door in Mr Rooney's face. Watch the pane of glass in the door. In all previous exterior views of the door, the pane is composed of about 4 horizontal pieces of glass. It is apparently a "jalousie" window that opens like a venetian blind, so there are no mouldings between each piece of glass. However, as soon as we see the inside of the door behind Jeanie, visible through the curtain is the silhouette of a "criss-cross" moulding grid, dividing the window into 9 panes of glass.
Continuity mistake: When Ferris and Sloane are in the pool, the Pepsi can behind Ferris changes position in different shots.
Continuity mistake: When Ferris, Sloan, and Cameron go to the Sears Tower they lean their heads on three separate windows. Ferris's window is the same as Cameron's. You can tell this when you see them look at the top and top right.
Visible crew/equipment: When Ferris picks up Sloan at school he puts her in the car and walks to the left of the screen. He then enters the Ferrari from the right of the screen. He obviously had to walk around the camera man to do this. You can also see a reflection moving back and forth on the driver's side door while this is unfolding. Presumably the cameraman's.
Answer: Sloane knew it was a hoax. Ferris would not have done something like that without her knowing. Rooney pretty much had figured it out, but could never prove anything. Once he was discovered inside the Bueller house (illegally) by Ferris' sister, anything he did know he would have to keep to himself.
raywest ★
Sloane starts to put her jacket on the moment that she sees the school nurse walk into the classroom, suggesting that Sloane already knew she would be called out, and she smiles to her classmates.