I'm curious to see if EVS issues a disclaimer with their braces... seems to me it would be pretty difficult to design a breaking point that protects the knee while not breaking a bone. Who's bone? Needless to say, there's a big difference in bone from one person to the next. I'm also not sure about the "people breaking femurs" due to braces statement, I'm sure it's happened, but... simple fact is, if your leg takes a big enough hit to break a bone, it's going to break rather you are wearing a brace or not. Tell ya what, apply the force it takes to break a femur to a knee; man I don't even want to think about how bad that would be.
I think as Speedway said, protecting the knee is more important than a bone... sure there are extremes to everything, but in general, having wrecked my knee and had surgery, I would have preferred to break a bone. The knee happened almost 20 years ago, still have problems with it. Once you do a knee, it's never the same.