Visible crew/equipment: When Brad and Stacey pull up in front of the bowling alley and Stacy opens her car door, several crew members can be seen reflected in her car door's window. (01:05:50)
Continuity mistake: When Mike is trying to get Mark to ask Stacey out, there is a shot of her behind the counter and Stacey's hair is pulled back on the sides in french braids with ribbons on the ends. Then when Mark approaches Stacey, her hair is pulled back in a clip. The first shot of Stacey with the braid, is actually cut from a scene later in the film, when Mark and Stacey talk at the counter. (00:27:35 - 00:28:20)
Answer: As a teacher myself, you learn to be able to recognize "problem" students fairly quickly (those that are going to be disruptive, late, etc on a regular basis). Mr. Hand is simply overly strict in regards to Spicoli unexcused tardy and seems not to allow students into class late, thus earning the student an absent. Mr. Hand does say he "will make you" attend his class. In addition, Spicoli was high and, in Mr. Hand's mind, disrespectful (Spicoli said "hey I know that kid" while they were talking) so Mr. Hand showed Spicoli disrespect in return as a way to teach him a lesson.
Bishop73