Please do share with us what firearm you, as a civilian, own that has a lethal range of over 12,000 yards.
As I mentioned in my earlier post, ignorance of the consequences of any and every possible scenario or discharging a firearm is no excuse in the eyes of the law. Before you pull the trigger on any firearm you better be willing to bet your life, and the life of everyone around you, that you know precisely where the bullet is going to hit and where it will ultimately end up. As I said, I know first hand, probably better than anyone else on this forum, what can happen to a person when they are ignorant of every possible consequence of pulling a trigger. If you're comfortable with looking a mother in the eye and explaining that you were "just so sure" that your shot wouldn't take that one in a million bounce and kill her child, go ahead and shoot. Just remember that if Murphy's Law enters into the equation in the worst way, you'll get to give your lame explanation of how you were just so sure that odd ricochet wouldn't happen to police, detectives, lawyers, judges as well as your new room mate for the next 20 years or so while writing your family and friends hoping that you'll live long enough to see them again.
If you think that sounds harsh, I assure you, that little explanation doesn't even begin to touch the reality of how horrible one simple mistake can be and how many lives can be permanently shattered just because you thought you were safe when you were shooting around people.