Unless "affecting the towing aircraft" means "ripping its tail off", in which case you're screwed no matter what height you're at. GA aircraft are probably a bit sturdier, but large cargo aircraft (based on large passenger aircraft) were simply not designed to pull anything, so I imagine you would need to add some kind of (pretty sturdy) reinforcement to the attachment point, which would mean extra costs and reduce the MTOW of the towing aircraft.