Yes, if they run of(f) the runway, they breaks in half, so they are builded this flimsy. That's why you pay extra for the warranty, so you can keep both halves. If an aircraft runs off the runway, it is not on a smooth surface. The aircraft structure is designed to land and taxi on a smooth surface. This is totally different than flying, since the wings lift the fuselage and are designed for some turbulence action. The landing gear is designed to take some punishment, but if the surface is too rough, the structure will fail, causing major damage to the ring segments in the fuselage.