Only time I rolled a tire was when a yahoo in a Ford Fairmont decided to gutterball it right beside me on Pacific Coast Highway, there was traffic and he obviously wanted to get ahead. I turned right and my rear axle caught his rear bumper. I then bounced crossed up rear to the other side, landed and rolled the tire. Valve broke right off, kicked the bike back straight underneath me and rolled it out to a stop.
Friends behind me a ways thought for sure I was going down, I am allergic to falling. Dressed the rim nicks when I got home and still have that wheel.
If I was on clinchers, I would have gone down.