I suppose you could slip. Then again, you could slip trying to jump it and end up with a nice scar on your shin like I've got.

My other barrier advice is to practice running (not walking). Speed will help you with your momentum. If you have a barrier you can use (I've got a portable PVC one), practice on flats, uphills, and downhills. Practice with your bike. Practice when you're tired. Practice, practice, practice.