We generally believe that there is a lot of value in what are often called “stop button” proposals, mostly not from a technical perspective, but as a social-political factor. As an example, I have in the past asked someone who worked at a large tech company whether they could shut down all of their servers if they wanted to. He said no. He didn't know where all of them were. There was no single person in the entire company who knew where all the servers were and what software was running on them.
As for creating legislation, I am not familiar, unfortunately, with the specific proposal you mention. There is a lot of value in this, but it sounds to me that the proposal pushes against development.
We cannot rely on waiting until we see a superintelligent system, because by the time we see one, it is already too late. It's quite likely that when the first superintelligent system gets built, we will not even recognize it as being that until quite a bit later, and that will be far too late.
It's very important—which is why there's a repeated emphasis on precursors—to make sure that such systems never get developed in the first place. To do this, we need to already be in the loop before such systems are built.