The clever thing here is that they are taking a position that is very hard for the gun rights lobby to oppose. After all, does anyone disagree with the position that when a firearm if not under your immediate control it should be secured? Michael Bane just talked about the need for safes in one of his podcasts.
Of course, the ad gives the false impression that such accidents are common, when they are not. It also omits the fact that such incidents have been dropping for over 100 years. However, most Americans don't know this.....