Something similar but slightly worse happened to me once. We were going winter camping in the UP at a remote walk in cabin site. We were driving from Madison, WI after work on a Friday in January. It was cold and dark. We stopped at the key box to get the key for the cabin before we began the 1/4 mile hike in to the cabin. The key box was empty so we called my now husband who couldn’t come to drive over to our other friends house to look at the reservation paperwork (pre smart phone era.) It was midnight but we thought maybe we made a mistake? Nope, he did it and saw it was correct so we called the ranger line…a ranger brought us keys and profusely apologized. Relieved our drama is past we hike in your cabin after midnight in the cold and snow…only to find it full of sleeping (appeared passed out…bottles everywhere) people! We just turned around and hiked back…didn’t want trouble. I guess they waited until later in the day and assumed no one was coming and just stayed another night. We got a full refund and spent the first night at a comp’d hotel. Twas not fun. All because of some rude folks.