As students around the Washington area return from Spring Break madness, many parents breathe a sign of relief at the thought of them being again tucked safely away in their dormitories.

But recent incidents, including a University of Maryland student awakening in her dorm room to being fondled by an intruder, show that even the multiple layers of security being used today can’t guarantee restricted access at residence halls. And high-tech measures can be rendered useless as simply as an 18-year-old holding a door open for the person behind them.