Continuity mistake: In the Nationals competition scene, Aubrey's hair is seen tied up, but soon after, her hair is down, and then it goes back to being tied, until she finally takes it down for the end of the performance.
Continuity mistake: During the Bella's performance of I Saw The Sign in which Beca starts singing Bulletproof, when Chloe sings the line "like me care for you" the camera focuses on the audience and there an older woman with glasses sitting next to a guy in a blue shirt, but in the next shot the woman has moved seats, and is now sitting next to a guy in a yellow shirt in the row behind the judges' table.
Continuity mistake: In the party scene when they show Bumper and Donald, a girl with a green shirt and a leather jacket walks down the aisle. When Fat Amy approaches Bumper, the same girl walks down the aisle as if she is just arriving.
Continuity mistake: At the second competition when Beca runs out, you can see the family walking down the hall with the mom, dad and son in that order from left to right. When Benji runs out after her, the kid is then in the middle.
Visible crew/equipment: When the girls are singing the Miley Cyrus song in the bus, the camera switches to an outside shot of the bus. The silhouette of the camera is reflecting in the left window.
Character mistake: When Jesse is talking to Becca about "The Breakfast Club," he tells her that the best song is "Don't You Forget About Me" which was recorded by Simple Minds because Billy Idol didn't want to do it. Steve Schiff and Keith Forsey composed "Don't You..." Billy Idol approached them, requesting to sing the track. Steve Forsey didn't want Idol to do it for the movie, and Forsey personally chose Simple Minds. Idol was eventually allowed to record his version of the song, and it's on his album "Billy Idol - Greatest Hits" as remastered in 2001. He stayed true to the original.
Continuity mistake: When the Treble's are singing "let it whip" in the activities fair, Donald changes from sitting on the wall, to standing on the stairs, then back to sitting.
Continuity mistake: In the scene where all the groups are together and having a party, Donald changes position several times. First he is standing next to Bumper and in the next shot he is dancing, the shot after he is again standing next to Bumper.
Continuity mistake: In the very beginning scene when the Treblemakers are singing "Please Don't Stop the Music", they do not have on sunglasses, then it goes to the commentators. When it goes back to the Trebles, they are wearing sunglasses, then a few seconds later they aren't again.
Continuity mistake: In the picnic scene, there is one extra in the background with a blue shirt and jean shorts that walks by three times.
Continuity mistake: When the Bellas are performing at the frat party, Chloe briefly turns her head to show that her hair is in an elaborate updo. In the scene immediately following that scene, Chloe's hairstyle changes to a bun pinned to the back of her head.
Continuity mistake: When Beca arrives during the fight scene you can see Denise behind Fat Amy and Chloe moved to approach Lily twice in between scenes.
Continuity mistake: During the shower scene where Beca and Chloe song Titanium, Beca begins the shower wearing gauged spike earrings but when Chloe startles her they are regular silver earrings and they remain that way for the rest of the scene.
Factual error: In the scene where the Bellas run out of gas, on their way to the second competition, it shows the gas gauge saying "unleaded fuel only." But when the bus runs out of gas it makes the sound that a diesel engine makes, not a regular gas engine.
Continuity mistake: The extras directly behind Chloe and Aubrey in the auditioning scene keep changing or disappearing, especially when Beca arrives.
Continuity mistake: At the very start of the film when Bumper is telling the Bellas that they are "awesome-ly horrible, I hate you, kill yourselves, sisters before misters," one of the members from the Trebles walking off stage behind him walks by twice in the same direction.
Answer: It wasn't just that she sang a song he likes, she sang arguably the most well-known song from his favorite film in front of a huge crowd of people. It was a public, heartfelt apology rather than the abrupt, private apology she gave earlier.
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