We have enough laws now. We don't need another one. The only law necessary is one that holds a person responsible for causing injuries to another that could have been prevented. Since taking off any safety shielding from a piece of equipment constitutes a preventable injury, doesn't matter if it's a mower chute, chain guard, PTO shaft sleeve, or the screen on your microwave oven. It's simple, generic enough to apply to most situations, and adds less to government costs than a bazzillion laws for every specific case anyone can think of.
So I guess that answers the question, "One would have to wonder if you thought there were too many laws in place if it was one of your family members got hurt or killed by one of these dip sticks who mow like this?"