As we were leaving Canyonlands Island in the Sky we witnessed a motorhome starting along the Shafer Trail. The Shafer Trail is a 4-wheel & ATV trail that starts on the top of the park and descends to the White Rock Rim trail about 1300 feet below the plateau and eventually goes on down and traverses the floor of the canyon 2000 feet below. It was built as a mining road. My assumption/hope is that after reading the many warnings posted a hundred yards down the road/trail a prompt retreat was executed. But, Hey its a rental!