I think they are referring to the bindings ability to keep you in and not eject you once you start putting a lot of weight on your nose/tails. That has nothing to do with the binding though, if you dins are too low you will eject every time.
Pretty much just how much contact area the binding has with the ski and how close together the screws ore on each binding piece. When the binding has a small contact area, and the screws are close together, the the ski can flex more under the bindings.
Yea those are some pretty bomber mad heavy bindings, sure don't think you could break them. They are good ig but you might as well just get pivots or something else that's half the price.