Surprisingly, many parents seem to think it's okay to let their teens run wild on prom night. They figure they'll soon be off to college anyhow—and may choose to look the other way when kids head to hotel rooms with booze-filled mini bars. It's also common for a group of teens to go to the beach or drive to the mountains and spend the weekend in a house rented by parents of one of the students.
And kids aren't the only ones to feel prom-time peer pressure. Parents may be coerced by other adults to allow their kids to have as much fun as possible, and no one wants to be the mom who's "ruining her kid's life."
Ultimately, it's up to you—even if your teen is 18. It's okay to forbid after-parties that make you feel uncomfortable, says Sabine—as long as you express the difficulty of the decision. Say, "I want you to have fun, but I'm concerned about a few risks. I need you to agree not to do X or Y in order to stay safe."