Another thing about a little key safety lock device on the gun: under stress, you will likely discover you have lost so much muscle control that you can no longer get it unlocked. You may drop the key from having trouble holding onto it. You'll have trouble inserting the key into the little hole, whacking the key into the side of the gun several times completely missing the key hole.
I won't go into details, but one time I had to dial a cell phone while under great stress. First, I dropped the phone. Then I had trouble flipping it open. Once open, I missed numbers and had to close the phone, open it again and then very deliberately force myself to slow down and carefully attempt to press each number without missing. Messing with a gun safety lock under stress would be even worse.
I won't go into details, but one time I had to dial a cell phone while under great stress. First, I dropped the phone. Then I had trouble flipping it open. Once open, I missed numbers and had to close the phone, open it again and then very deliberately force myself to slow down and carefully attempt to press each number without missing. Messing with a gun safety lock under stress would be even worse.