Well if you wrapped the kevlar belt arround the fuselage for a fair distance forward and aft of the props, then when a prop failed the belt would still be there with the prop blade stuck in it, but the fuselage would be crushed almost all the way arround by the deflecting belt, not good for flyback purposes.
Give a thought to the prop trajectory and tumble as well. It reminds me of a bolo, it can't miss creating a 180 degree swath or more of damage.