The difference is in a different venue they would have had to charge him with some sort of weird law that has nothing to do with safe storage, because free america doesn't have storage regulations. I can legally store a gun in a sewer drain in NH if I want to, regardless of the fact that it is a terminally stupid idea. At that point if the police wanted to charge him on something they'd have to use some other law that has little or nothing to do with guns. For example, if it was in a public park or something they might try to argue that he supplied minors with a firearm because some kids saw him stash it in a bush or something like that. They'd basically have to go WAY out of their way to prosecute him, and odds are pretty good that it would fail.
Bear in mind that in free states guns aren't really treated as not much different than a bottle of booze in terms of storage (and some states, even less than that) absent some special circumstances surrounding the location of the object. Like Bill Nance says, some states have child endangerment laws and that's about it, and most of them are only incident related- like a kid shooting someone with a gun they found, etc. Even in those cases whether or not someone gets charged depends on the level of vicarious liability style of determination going on. For example a handgun locked up in a car would not fall under this, but leaving a gun in the junk drawer in a house known to be occupied by minors, might, if, and only if, something bad happens.
-Mike