by removing the ground they are saving their own life. I was a technician in a home that was struck by lightning prior to me being there. I was shocked until I was unconscious by a dish network receiver when I placed my right hand on the casing and my left hand grabbed the cable fitting (that was grounded in the basement) resulting in a completion of the circuit. I survived thankfully but, I cannot get help for the injuries I sustained. (or that I was left with) due to the fact of nature. by requiring this, it eliminates the danger of electrocution.. there are not many cases of this but, there will be if they are not careful.