That’s a very interesting question. And by interesting I really mean stupid.
But for the sake of argument and maybe other readers who missed this blatant plot-point in the 80s comedy classic, I’ll try to explain it to you.
After Joyce Hyser’s character, Terry, feels that her articles are not being taken seriously because she’s a woman and doesn’t get her dream newspaper intern job, she decides to enroll in a new school as a young man to prove that it’s because of the sexism. However, before she “became the male Terry” she also made a pact with a neighborhood Warlock to get powers in exchange for two human souls. One of these powers was the ability to alter reality hence why no one can tell “She’s” a “He” even though it’s fairly obvious. This is the main reason why no one at her original school knows she’s gone either. By mind manipulation she made it seem like she was still attending classes, taking tests and going to her school’s prom all the while she was manipulating the new school’s students and faculty. This is also evident by the way she hides her sublime breasts without wearing a bra. And even though I don’t have the deleted scenes or working script to prove this to you, it’s painfully obvious isn’t it?
Oh, and the two souls that she exchanged to the Warlock were her own parents. They were never on vacation in the first place but dead—sacrificed to the Warlock.
Your picture pal,