What you are seeing are the aerodynamic plastic sheaths coming off, not the blades. The current design is VERY strong. The sheaths are replaceable, as are the blades, and can be ordered seperately (sheaths/blades in one package).

Check out the link I posted above. See those green sheaths? That's what flies off when you hit the bird, because the blade slices through the sheath. That's how it's designed.