Many, many years ago, it was my turn to run the Sunday Night ARES net, when I lived up in State College. When I made the pro forma call for "emergency or priority traffic", someone actually did come back to report a traffic accident. I put the net on stand by, activated the auto patch, and called the borough cops.
If you're wondering why no one used a cell phone, this was around 1980-81. No cell phones yet. And, I wasn't home at the time, but standing in a parking lot (long unrelated story), so using the landline was out.
That's the only one that comes to mind.