The shear-pins (the weak link) on a conventional towbar will not prevent the tug-driver from ripping the nosegear out of the airplane. The shear-pins are there to prevent the towbar from trying to turn the nosegear if the steering is pressurized, or to turn the nosegear past maximum angle.
As for pushing and pulling, the aircraft will either move it or loose it...
Ever stomped on a beer-can? That's the sound right there.. Horrible..
