Shooting upward is stupid and definitely against the safe handling rules (every gun is loaded (even when you're told it's not, check it for yourself), keep your booger hook (finger) off the bang switch (trigger) until ready to fire, never point at anything you're not willing to shoot/destroy, and only shoot at a known (visible, usually) target when you know whats beyond your target).
Thinking on the terminal velocity of a penny dropped from a tall building (it can sting, but that's it), I was planning to refute the 'several people getting killed this year by falling bullets' contention. BUT upon looking it up, it looks like while very few get killed by falling bullets (tragically, children are likelier to be lethally damaged if hit, and two kids seem to have been killed in 2012 and 2013 by falling bullets), the smaller aerodynamic ones, even from a handgun, can break the skin and perhaps crack skulls (a Texas Senator apparently got crowned by a falling .223 bullet and it fragmented and one fragment cracked his skull, reaching the top of the brain. He lived, but obviously needed the fragment to be surgically removed).
The more massive bullets (hunting/"battle rifle" bullets) are going to have more terminal energy due to their greater mass, so are likely more damaging. One reference I saw reported that at least 20 were killed (by what I presume were 7.62×39 jacketed (FMJ) bullets) in the celebration after the killing of Saddam Hussein's sons in 2003. I that case, I suspect that the volume of fire (possibly hundreds of men firing upward with at least 30 rounds each of full auto fire) while in a crowd significantly increased the incidence of people getting hit.
The lucky bit is that anyone getting hit is unlikely even in an urban area, but it still has happened. It's definitely a stupidly dangerous practice.
So yeah, it's possible that a person (god forbid a kid) could get hit by an idiot shooting up, and anyone doing so deserves to be getting decked by his friends and family, at a minimum. If he hits anyone (or anything) it should be prosecuted as if he had pointed and shot at the target (ethically, if not legally, I'd hold him for attempted murder, but most likely he'd get reckless endangerment or negligent homicide)
