Teenagers enjoy making out in cars. This is probably because they expect that no one will see them, and they won't see anyone. However, teenagers at Make-Out Point ironically tend to be the first witnesses of the alien invasion, or the zombie apocalypse, or the impending shortage of toilet paper. Quite often, they will be brutally murdered to show that the Monster of the Week means business. Why? Perhaps Rule of Funny. Perhaps they are considered Acceptable Targets. (Bonus if they get shot at.) Somewhat of a Dead Horse Trope nowadays, considering it is parodied more than it is used.