Audio problem: Throughout the final sequence, when Harry and Nora are in the jeep and being chased by the police cars onto the field by the gym, many of the words Harry says are out of sync with his mouth.
Audio problem: Just about every time someone starts or stops a cassette tape, we can see that they're either faking it or pressing the wrong button. In one shot, the 'Pause' button is down both before and after the actor presses 'Play,' which would of course mean that the tape shouldn't play at all.
Audio problem: When Nora is trying to tell Mark that it wasn't his fault that the boy committed suicide, her lips aren't in sync with what she is saying. (00:38:00)
Audio problem: When the reporter is filming the punk lighting smoke bombs in front of the school, he is encouraging his camera man to film the punk. His mouth doesn't match what he's saying briefly.
Audio problem: Near the end when Mark is shouting for the kids to start their own stations, in the wide shot the audio doesn't match up that well with what he's saying.
Audio problem: Around half an hour into the film, some kids are listening to a tape of the radio show and a teacher takes the tape out because he doesn't like the content. As he takes the tape out, the audio ends right after the tape door opens, when it should have ended a little sooner, if it was actually coming from the tape player. (00:32:35)
Chosen answer: Well, with no actual scene where he confesses, it's left up to us to wonder. Personally, I find it unlikely that he'd actually admit the whole thing to his parents, but they're not stupid and already had their suspicions, so the lack of any great surprise on his father's part isn't unreasonable. You also have to remember that Mark's voice changer had already broken before they drove down to the crowd - his father would have easily recognised his voice before his actual arrival, giving him a certain amount of time to get through the initial shock.
Tailkinker