Even as a supporter of 2nd amendment rights, I think the parents should be penalized for letting a 4 year old get ahold of a loaded gun. Letting him get ahold of a gun in the first place is bad enough, but leaving a loaded gun out in the open where a 4 year old has access to it is unacceptable. These parents have rights, but they are reclessly putting their child (and every one else's children in this case) in danger. Now I'm not saying that everyone needs to keep guns in safes with locks on them, but if you're going to leave your guns out, you need to keep them at least out of reach of your damn4 year old, and someone should at least have gone over the Eddie Eagle steps with him by now.
I hope these parents are penalized in some way, because this is entirely their fault.