After the Dawson shooting, the police seized a weapon from someone they thought could be a copycat killer and commit the same horrible crime. They seized the weapon, which means there was a possibility that the person could have killed someone with it. It's not a certainty, but a possibility.
How can you make the categorical statement, the sweeping statement, that the registry could not possibly have saved even one life over the course of 10 years, when the police went and got a gun from a possible copycat? How can you make such a sweeping statement? I know it's very hard to come up with anecdotal, 100% certain evidence that a life has been saved. I could say I'm not here today because of the 100-kilometre-an-hour speed limit. I could say there's no proof that the 100 kilometre-an-hour-speed limit has saved my life, but we know that in the aggregate, the speed limit does save lives.
How can you make such categorical sweeping statements?