While someone just happening to have an old-fashioned oscilloscope with her that day is a gag (best appreciated by those who have at some point lifted one), a high school is the one place in which it would be least implausible that a student would just happen to have an oscilloscope with her. She could have brought one to school to use or to present in a class that day, or perhaps checked one out to use at home.who just carries an osciloscope around?