Factual error: After Gale talks to Sidney and Sidney seems doubtful of Cotton Weary's guilt, Kenny the Cameraman says to Gale, "Do you wanna go live?". Gale is an anchor/reporter for a tabloid-like show called "Top Story" (Sort of like "Current Affair", "Inside Edition", or "Hard Copy"). She does not work for CBS News or NBC News, etc. She does not have the power to "go live" and interrupt regular television programming. (00:41:55)
Factual error: During the scene where the group of friends is watching Halloween, one boy says something like "Why do they do that? The blood is all wrong. It's too red." The problem is, during that part of the movie, no blood is shown or even implied. Bob is just pinned against the wall. (01:12:25)
Factual error: Gale Weathers points the gun at Billy and tries to shoot him, but the trigger doesn't pull back. This is explained by Billy when he says that the safety was on. Fine. But that gun is a Beretta 92F, and on a Beretta 92F when the safety is on, the trigger WILL pull back, but no round will fire. (01:37:20)
Factual error: At the end when they are loading Dewey into the ambulance on the stretcher, it is standard procedure to put the patient neck brace when they receive any type of unknown injuries (stab wounds) to their back as Dewey did - it was notably absent.
Factual error: Throughout the movie there is constant reference to the Sheriff; Burke is the sheriff, Dewey works for the sheriff (and he will become the sheriff in Scream 4, with the same mistake happening), but the car Dewey uses is marked "Woodsboro Police."
Factual error: At one point when the partygoers are watching Halloween, Randy alerts them about the "obligatory tit shot" and afterwards the viewers react with great satisfaction, however, in the referenced scene in Halloween, the naked breasts are actually kept out of frame.
Answer: Landline phones like the one used in the movie cannot dial out a phone number while the line is active. Considering the killer is continuously calling her, she can't dial out on the phone line. This is referenced in the movie itself when her parents arrive home, attempt to dial 911, and can't due to the line still being active.