I find Rog's measure very good because it gives more space for deformation and also because the impact is not concentrated on one ugly point of the screw thread but it is distributed over the surface.
And on the other hand, I totally agree with Graham. Nothing is worse than a bending of the chassis. I had an old Mercedes with a trailer hitch many years ago. Another car could not brake in time and my car was totaled because the whole rear part from the rear window on bent down. The trailer hitch was I think somewhere attached to the axle or the side members.
