the advice regarding the towing pole on the focus may be because it could shock the airbag into activating,
As for the rope snapping , that I am afraid is the problem of the rope not being strong enough or most probably you and the driver of the car being towed,
When towing a car it is for the driver being towed to brake first to keep the rope taught to stop the rope snatching and snapping when you accelerate off,
in a nutshell use a rope up to the job , keep it tight between the vehicles and no sudden acceleration then you should be just fine.....
To add to that towing poles are not fool proof either , I once witnessed the AA rescuing someone who had broke down at some traffic lights, he put the pole on and got in and pulled the car straight into the traffic light pole smashing the front end badly , the moral of the story , always make sure your key is in the ignition and the steering lock is off ......