I beg to differ, Notso. There is more to pushback than a line on the door and relying on the shear pins. For example, 737-300 again, did you know the maximum tow force permissible is halved beyond 45 degrees? Most do not. However limits are there in the maintenance manuals, which are approved documents, which means no one may deviate from them! Approved documents apply to everyone who interacts with the aircraft, same as flight crew and engineers.
Rampman is to be commended for raising his awareness. The real culprits here may be the quality departments of the aircraft operators who fail to satisfy themselves of adequate training for their contractors.