The population density of the region is an established fact (see my first post). Reports indicated that fewer people were home in the afternoon ... it's a simple inference from the fact that it's a residential neighborhood that the population density of the neighborhood would fall during working hours, thus reducing the chance of a hit. Even if you disagree with that inference, and I'm not sure how you could logically support such a position, there is still only a 0.19% chance that a cannonball fired along that path would actually hit someone. Thus, no injuries is hardly a fluke.
Don't misunderstand what Psion and I are saying. Of course any potential risk to life and limb is something that should be taken seriously. The odds of, say, two planes colliding in flight may be low, but even with a low probability, the consequences are grave enough that we employ radar and air traffic control and all possible precautions to get the risk as low as we possibly can. And of course the Mythbusters always take precautions to ensure the safety of anyone that they realistically expect could be endangered by a test with explosives or projectile weapons, because that's just common sense. But there's a difference between responsible management of a risk and irresponsible sensationalizing of a risk. It is sensationalist and wrong to say "It's a miracle nobody was killed." That's putting emotional reflex ahead of the facts. There was a genuine risk of injury in this unfortunate incident, but risk is cause for reasonable caution, not hysterical panic. Stirring up unjustified fears is not a constructive reaction here. Both our calculations and just plain common sense should agree that the odds of an unaimed projectile hitting someone a kilometer away are very low. Certainly they're significant enough that every reasonable precaution should be taken not to fire unaimed projectiles through populated areas, and nobody can validly deny that the Mythbusters took every reasonable precaution. This was a one-in-a-million fluke and should not be taken to reflect negatively on their caution or responsibility, let alone on that of Sgt. Nelson and the staff of the Alameda bomb range. Certainly we should breathe a sigh of relief that that one-in-a-thousand event of someone being seriously injured or killed didn't happen. It could've happened, and it's great that it didn't. But it's just plain wrong to talk about it as though it were likely to happen. That's like getting off a plane and saying it's a miracle you didn't crash. Plane crashes do happen, and they're terrible when they do, and it's certainly worth guarding against them, but that doesn't mean they're more likely than the alternative.
And I did not mean, nor do I think I did, to imply that the Mythbusters, Discover, the bomb range or anyone acted poorly in this case.
I think we're all in agreement on that. The Mythbusters team did a great job addressing the mistake. My only disappointment is that they're not going to take advantage of it to present a "learning opportunity" episode covering this and other Mythbusters accidents. We're just debating the value of statements like "lucky no one was hurt" at this point. And it's a fun, interesting debate so far.
Right, because a key part of science is being able to learn from failures, or at least from things that don't go the way you expected. What started this for me was the discussion of responsibility. It's certainly responsible for the Mythbusters to respect the families' wishes if they prefer not to have this footage used, but I think that if the families were receptive, then using this as an opportunity to teach some science (and some statistics) would also be a responsible way of dealing with it, because the intent would be constructive rather than exploitative. Maybe the issue is how we define "lucky." I think when people generally say things like that, what they mean is "It's a relief nobody was hurt," and I certainly can't argue with that. But it should be understand that it's not a great surprise that nobody was hurt, because that was the most likely outcome. It's hard enough to hit targets you're deliberately aiming for. This rogue cannonball was an incredible fluke event to begin with; if it had hit someone purely by random chance, that would've been an even more incredible fluke. It would be whatever the evil equivalent of a miracle is. Hmm. Does it say something about our cultural perception of the probability of good vs. bad events that we have a word for "extremely unlikely positive event caused by divine intervention" -- namely "miracle" -- but don't have an equivalent word for "extremely unlikely negative event caused by demonic intervention"? Do we just take it for granted that surprisingly bad events are likely to happen without needing special explanation, whereas surprisingly good events are so unlikely that they require divine intervention? That kind of "expect the worst" mentality might be related to the same kind of thinking that prompts the "It's amazing nobody was killed" reaction here. Of course, I'm as human as anyone and I'm certainly not immune to overreacting to the threat of low-probability negative outcomes. It's why I avoided flying for many years. (These days I'm okay with flying per se, but I have issues with the cost and the x-ray exposure from airport scanners. Although the latter is arguably a low-probability risk too.)