I've gotten a call like that but it ended up being a fatality at scene when we finally found the driver.
We get calls similar to that in Florida frequently but it is "boat without driver". It then becomes a search and rescue until it is determined to be worked as a recovery instead.
My "WTF" followed by "were you doing" usually comes literally out of my mouth in RT more than EMS (after 30 years) these days in both the ED and LTC floor. For example; patients who are vent dependent quads that come in from the patio or home stoned from smoking marijuana is my pet peeve even after I told them it dries out their secretions. Proper hydration is important before engaging in this activity. At least I usually get them to stop smoking cigarettes.