Aside from the violation of protecting the GEC like that, I think you might cite 300.10:
Electrical Continuity of Metal Raceways and Enclosures: Metal raceways, cable armor, and other metal enclusres for conductors shall be metallically joined together into a continuous electric conductor and shall be connected to all boxes, fittings, and cabinets so as to provide effective electrical continuity. Unless specifically permitted elsewhere in this Code, raceways and cable assemblies shall be mechanically secured to boxes, fittings, cabinets and other enclosures.
My emphasis on the part that seems to apply.