I also notice something similar on my car. As far as I know, any body has its own natural torsion coefficient, and you can't rigidly weld everything to zero - the metal will simply crack near the seam from overvoltage. I'm curious how modern stands distinguish dangerous deformation from permissible factory deflection? Are there any workshops where they calculate the resistance of fatigue zones on computer models before welding, or do they just weld thick steel corners everywhere out of old habit?