An unlocked door doesn’t always mean open. That’s why knocking on a closed bathroom door is always a good idea (I might know this from experience).

Two kids in Oregon City learned that lesson the hard way last night: Less than six minutes after getting a call from Sonitrol Pacific, Clackamas county police caught them inside a local school just after midnight last night.

Sonitrol’s unique audio detection picked up on voices and movement coming from a classroom. Knowing that no employees were scheduled to be in the school at that time of night, Operator Jessica Culver dispatched police and called school officials. A few minutes later, police were on site. With real-time direction from Jessica, the responders immediately found two kids inside and returned them to their parents.

No damage or theft was visible—the kids had found an unlocked door and walked in.

Lesson of the day: Unlocked door? Knock first. Not your property? Stay out!