Bad parents blame their carelessness on the most unreasonable things, I mean come on! The Wii Remote? I could understand if she went through their stuff and she was already taught what not to do, even then they COULD put it higher up somewhere out of her reach AND could still get to it quickly if they really needed to (if their is any type of fear that they may need to use the gun for self-defense, even then someone can more than likely rush to the area it was locked and stowed away if they hid the gun that way).
She is still a baby and still was learning. They need to not only keep dangerous stuff out of reach, but they also need to take time with her to teach her since she is in the process of growing out of her toddler age.
Also if she truly got the idea from the Wii, would it make sense NOT to play those shooting games on the Wii in front of her as well?
There is no excuse for them, I truly am sad to hear the little girl had parents like that since that could not have been helped.