When in the limo to school and then when he gets out, Sebastian's tie knot changes between shots (watch the colors.)
When we see Sebastian's father cuffed to the bed on his boat, the chain between the handcuffs is rather long. But his father is back at home, still with them on, the chain is much shorter.
The exterior of the limo that is shown taking Sebastian and Kathryn to school changes from the time that it is initially shown to the time it is seen in front of the school. The first limo shown has different rims than the one that shows up in front of the school. The first limo also lacks the chrome trim around the bottom of the doors that the one that pulls up in front of the school has.
During Kathryn's orientation speech, Danielle's hair switches from being behind her ear to over it in almost every shot.
When Sebastian gets up from the bed, he has chest hair. While heading towards the shower in the bathroom, the chest hair is gone and he has lost a lot of weight. This is because the shower scene with the lesbian twins was filmed over a year after principle photography ended.
The lesbian twins that share the shower with Sebastian are seen wearing flesh-colored panties in one brief shot.
When Sebastian's father is on the phone to his "accountant" and Sebastian walks in, to the right hand side of the screen above the sofa his father is sitting on, you can see the head of a crew-member in the whole shot.
A crew member is reflected on the limo door that Cherie is entering at the end of the movie.
At the start of the film after Sebastian leaves the principal's office, as the principal says "Pansy" the reflection of a boom mic in the glass door above him is clearly visible.
The Assistant Headmaster refers to Headmaster Sherman as Headmaster Hargrove. Hargrove was that character's original last name, from the unaired TV series, and was missed, in the dialogue, when the series was edited into this film.
When Kathryn is seen talking to Asst. Headmaster Muller, he mentions having been called into Headmaster Hargrove's office, instead of Headmaster Sherman. This was not corrected when the character names were changed from the TV series to the movie.