I think I have fallen with any/all foot retention systems used today. Even without foot retention systems, now that I think about it. My falls are more frequent with foot retention systems. They have all been low speed events, more embarassing than painful. The typical clipless fall now is with a slow speed turn around, as I start to loose it, I have the delusion that I can save it right until I hit the ground. For low traction road situations (like this winter?), I think I would skip the foot retention devices.