It would certainly help as would not flying over people to begin with. There is no quick way to shutdown a DJI drone. I think they should add a kill switch or button on the controller to stop the props as fast as possible.
Don't forget: Even though you can kill power to the props, simply falling to Earth will make the props turn. If the distance to Earth is sufficient, those props could be spinning fast enough to cause further injury to the unlucky and innocent bystander.