Continuity mistake: When Ian films the Chipettes during the sing-off, he says, "If you like what you see then call Ian Hawke." But when someone else plays the video back later, he says, "If you're interested, then call Ian Hawke."
Continuity mistake: When Toby comes to get the chipmunks at school he breaks a drum-head. He breaks the same drum-head twice.
Continuity mistake: At the Chipmunk's house, the poster on the wall outside the kitchen keeps changing.
Continuity mistake: Near the end of the movie, Alvin and Dave are discussing something while turning the lights on and off over and over. In one of the shots, Alvin flips the switch down. When we cut back to Alvin the switch is up again, even though he hasn't flipped it back up.
Continuity mistake: During the entire film, the house number on the front of the house that the boys live in changes. In some scenes it's 1516 and in others it's 1958.
Other mistake: When The Chipettes perform their audition for Ian Hawke they are standing on the Jett Records sign on the roof of the Jett Records building. In order for the sign to read correctly from the street, Ian and The Chipettes should have a backwards view of the lettering. In the movie the sign reads correctly from Ian and The Chipettes point of view, meaning that it is giving a backwards view to the street, ie. it is the wrong way round.
Other mistake: The code for the lock on the cage near the end of the movie when the the girls are trapped in the cage is 777, not 111.
Continuity mistake: At the sing-off, when the Chipettes are singing, Ian uses his phone to make a video. At the end, he winks to his phone. However, when the video is seen on a website by some record executives, Ian does not wink.
Continuity mistake: When the bullies are having lunch outside, Simon shows up and says "Quick announcement, I'm in-charge of cleaning." A piece of garbage suddenly appears on the floor, out of nowhere, between shots.
Audio problem: During lunch at school, Alvin tells an anecdote about Beyonce and all the girls laugh loudly, yet their mouths aren't moving.
Audio problem: Near the end of the movie, Alvin, Brittany, Jeanette and Ellanore are hanging tight to the helicopter. Jeanette jumps down to catch the remote. When she catches it you can hear "Way to go Jean!" Neither Alvin, Brittany, or Ellanore moves their mouth.
Continuity mistake: While having lunch at school, after Alvin talks about Beyonce, Theo turns around and the angle changes. The bag of chips behind swaps from pointing in an 8 o'clock direction to a 6 o'clock.
Chosen answer: Because they're more sensitive and weaker.