(at around 14 mins) There's a scene where Kale is shown putting stickers on his ankle bracelet. In a following scene, you can see the ankle bracelet, but there are no stickers on it.
(at around 1h 30 mins) When Kale first falls through the boards and into the pit under Mr. Turner's house, the water is very dirty and murky. Shortly after, when Mr. Turner falls into the pit himself, the water in the pit is very clear and clean.
(at around 1h 28 mins) When Kale breaks into Mr. Turner's house with the garden shears, he cleanly knocks out the full pane of glass. But, when Officer Gutierrez responds to the call, he sees large shards of glass still in the window pane of Mr. Turner's house.
The Lexus at Mr. Turner's house at the beginning of the Movie is a Lexus IS. At the end of the movie when Kale and his mother leave the house the Lexus in the garage is a GS model.
(at around 37 mins) The first time that Ashley goes into Kale's room when Kale and Ronald are trying to clean it up, Kale puts a shirt on top of the tower of Twinkie, but in the next two scenes the Twinkie tower is uncovered then covered again.
(at around 28 mins) When Kale is watching Ashley do yoga in her room for the first time while eating popcorn, she stops and looks at Kale. He then indicates how she can't see him as it's too dark in his father's office room to see him watching her. Yet the camera then shows 2-3 lamps on in the room lighting him and the room up.
(at around 1h 19 mins) When Kale gets the text message from Ronnie to "look at his TV", the phone icon on his phone is on vibrate mode, so he shouldn't have heard the "Me So Horny" ring-tone.
(at around 10 mins) The menu on Kale's Xbox is much larger than the normal Xbox menu. (Most likely to make the "Connect to Xbox Live" button easier to see).
(at around 1h 22 mins) Kale sees Mr. Turner's reflection on the Apple Cinema display in his room. Apple LCD displays have a non-glare finish so a reflection would not have appeared. The display didn't appear to have a reflective surface in earlier shots.
Kale sets out a perimeter in his garden to determine how far he can go outside without setting off his ankle lock. The perimeter is set out in straight lines (square), but it should have been a circle.
(at around 9 mins) When the house arrest lady is explaining the ankle bracelet to him she says "they will know where you are 25/7." However, this could have been said by the character to emphasize that Kale's movements are always being watched.
(at around 20 mins) When Kale is walking around his yard marking the area that he can stay in, he makes a square. However if he is only allowed to be within a 100 foot radius of the ankle monitor, the area would be a circle.
(at around 10 mins) When Kale presses the menu button on the Xbox controller, he's supposed to be offline, but you can see that he has 2 new messages button and that there are 2 friends online, so he's still online.
(at around 1h 30 mins) When Kale looks into the air shaft with a light bulb, the ray of light used in a movie is actually flashlight. It shows spots of light, instead of a real light bulb, which would have lit up the entire room.
(at around 1h 26 mins) Kale carefully removes the duct tape that is wrapped around his face. But he just pulls off the rest of it with ease when in reality it would have been tightly stuck to his hair.
(at around 10 mins) When Kale's Xbox Live account gets closed, he tries to log back in and gets a "ACCESS DENIED" message. But if his account was closed, he should've gotten a log in error message, saying that his username or password was incorrect.
(at around 57 mins) When iPods are disconnected from audio accessories (docks, earphones, etc.), they stop playback and pause. But when Ashley pulls out Kale's iPod from the dock, he puts it back in and the music continues playback, without him unpausing it.
How the underage Greenwood boys were able to subscribe to an Adult Network goes unexplained.
(at around 1h 5 mins) While seated in the car, Turner's dialogue and his lip movements don't match.
Right before Kale goes to rescue his mother at Turner's house, he tells Ashley to wait for the police. Yet, she doesn't appear when Officer Gutierrez arrives, thus doesn't warn him about Turner.
(at around 7 mins) Despite being a (likely native) Spanish teacher, when Mr. Gutierrez is asking Kale his plans for the summer he says "Usted, ¿qué vas a hacer?" ("You, what are you going to do?"), which is badly constructed. The correct phrase in Spanish is either "Tú, ¿qué vas a hacer?" (familiar form) or "Usted, ¿qué va a hacer?" (formal form).
(at around 1h 8 mins) When Kale and Ronnie are talking to Ashley about her possibly having Stockholm syndrome, she gets a call from her mom. She says "Hi, no, I'm not over here". She gave it away. What she should have said was "Hi, no, I'm not over there".