I only had one little fall this winter... hit some black ice on the extra bike and just a touch of the back brake caused the wheel to slide out and when a bike this long starts to fishtail it's pretty amazing... and hard to recover from.
I actually layed it down on purpose and stepped off and that's when I fell... figured I would have slid right into a busy intersection if I hadn't.
The bike is so amazingly stable it caught me off guard.