A NICE NEIGHBORHOOD??
You might remind her that several years ago in a Beverly Hills, CA mansion, seven people were stabbed to death by three women & one man. There were sent there by Charles Manson. A couple of days later, a married couple were stabbed to death in another mansion in the hills above Glendale, CA - sent there by the same P.O.S.
As for a gun-related accident in the home, you might inform her that guns are way down on the list of dangers to children in the home; far below accidental ingestion of cleaning chemicals & prescription drugs, & playing with matches or the danger of swimming pools. I'm assuming she is not planning to ban all of these items from the home - just locking them up like you've already done with the gun.
I just read that auto accidents are the #1 killer of children.