I can't make it fall. I've tried since reading your post. My works fine on any surface or position. It's a great accessory so far.
After another couch session, this is my definitive assessment. Depending on what I am wearing, the bottom edge of this case has the tendency to slide down toward me while the folded triangle sticks, causing the triangle to rotate thus resulting in a flop.
The reason there are varying opinions on this flop issue is that there are variables: finishes of the leather resulting in different coefficient of static friction, what the user wears, body shape, sitting angle, etc.
For me, using brown leather case, the flop happens when I sit on a couch with my legs up so the iPad is on an incline. But it is a non problem because since I am on a incline, there is no need for the supporting triangle.
It is truly a great accessory: minimal, functional, elegant. Forget what the pundit say - if what I describe interests you, you should try it for yourself. I normally don't like cases because they add weight, are ugly, cumbersome. This on the other hand complement the design of the iPad, like a beautiful frame for a photo.
