I set my Shapeoko back about 5 inches on its bench, then created a drop zone out of low scraps of wood directly under the BitSetter parking location. No more dropped bits, no more rolling off the bench!
The only downside is that I have to slide the shapeoko to the edge of the bench if I want to do any front-clamping - which I have not had to do more than once. I just kept the edges of the drop zone lower than the bottom of the Shapeoko so it can slide over the top of the zone.
Here’s a photo:
