A gun doesn't know if a person is an idiot or not either, but it doesn't stop it from becoming a killing machine does it.
A trigger lock keeps kids free from harm, relatively at least. My uncle hada gun in his sick drawer. as kids we took it out to look at everytime he went out. It was stored empty, open and with a big old pad lock through it. Had he not done that, hell yes it's likely my cuz nd I would have killed each other... we were dumb kids.