Continuity mistake: At the start of the pep rally, Mr. Ames takes a seat behind Austin in the close-up. Next shot facing the crowd, when Coach steps up to the stage, Austin's father is gone - his seat is empty, but a couple of shots later Mr. Ames is still there. Additionally, Sam and Carter are also gone in the crowd shot. (01:09:40)
Continuity mistake: At Rhonda's house, when Sam says, "You sure do have a knack for taking something simple and making it beautiful," the red bowl is beside her. After Rhonda shows Sam the white gown, the camera pans back toward the table top and the lace mask suddenly and deliberately appears and is leaning against the bowl.
Continuity mistake: When Austin is putting up the Cinderella fliers with Ryan and David, his hair is considerably shorter than the following shots, such as when he goes to the diner and talks to Sam at the counter.
Continuity mistake: When Sam is taking batting practice during school, she hits a ball at Carter's feet. If you look at the way she hits the ball, she pops it up. Then the very next pitch she check swings and crushes the ball to Austin Ames.
Continuity mistake: When Austin is typing to Sam from his bedroom, the very first book on the shelf in the background keeps changing, over and over again. This occurs near the start, when they are still unknown to each other, and also when he tries to write to her after the pep rally incident.
Continuity mistake: During Sam and Austin's dancing outdoors, Sam's hand shifts. In one shot it is completely over his shoulder and in the next shot it is on his shoulder. We see her hand the entire time so there is no time for her to move it without seeing it.
Continuity mistake: When Sam is running away from Austin at the dance, the bottom of her dress is very dirty, it's almost black. When she runs inside and runs up the stairs, her dress is white again. This is confirmed on the commentary.
Continuity mistake: When Fiona is opening Sam's college envelope she puts a magazine and papers under her arm, but in the next shot there are only papers.
Continuity mistake: When Brianna and Gabriella are in the car wash, they get covered in soap suds. When they fall on top of the car, they are noticeably drier.
Continuity mistake: Right after the twin's swimming instructor says, "Push it ladies," three times, Gabriella reaches for Brianna's hands and grabs them. In the shot right after the fart, Gabriella is still reaching for Brianna's hands.
Continuity mistake: When Sam and Carter leave the dance and run to the Mercedes so Sam can get back to the diner by midnight, in the long shot before they reach the car we see, one, that Sam pulls off her mask as she's running, and two, there's a rearview mirror on the Mercedes. In the following shots the mask is still on her face, and the rearview mirror has vanished again.
Continuity mistake: At the start, when Sam is at school and texts "We talked this morning", her cell antenna is pulled out, but next shot the antenna is suddenly back in, though Sam's hands are in the same place.
Continuity mistake: When Rhonda tells Fiona that she is going to find a place to put her six dollar pedicure, she puts her hand on the counter. In the next shot (from the back), her hand is down by her side.
Continuity mistake: When Sam and Austin are talking about Princeton (through chatting and voiceover), Sam asks Austin if he's told his dad that he wants to go to Princeton, Austin types "He's got a whole other plan." but he says "He HAS a whole other."
Continuity mistake: In the first shot of the scene with Gabriella and Brianna talking with Shelby and her friends, convincing her that Sam tried to steal Austin away from her, Brianna is sitting with her arms folded on the table, but in the next shot, she's holding a tissue (which was not present in the previous shot) right before she says "Our stepsister has always been jealous of you" and blows her nose. (Visible on fullscreen DVD).
Answer: Yes, this happens in most schools. The reason is that students are more likely to pay attention to announcements that are not made by a boring school employee. In many American schools, we have a phenomenon known as "home room". This is a short period usually first thing in the morning that is non-instructional when announcements are made, forms are filled out, and administrivial functions that don't have anything to do with any one class. At schools that don't have this, they have a thing called "study hall" or "independent study" which is a period where you sit in a classroom and work on your assignments, special functions for the school admin. like you are talking about are frequently done at these periods by students who are "working in the office" rather than studying. Then, there are schools that actually have classes in journalism, broadcasting, etc. where this activity would be part of the schoolwork.
Myridon