Through a series of blunders, government can use lethal force against you for sawing off a shotgun blade. (I might stress that point too much…) Now, other factors must come in to play. Does the mad-bomber intend to use said weapon against people? Perhaps – it’s a stretch, I know – he just wants to make craters. We always tend to think like present statist types and jump right to violence. I am naive, I know, but I would handle such a matter in this way: if he had made his intentions clear and was seeking to kill people, the [unfinished] bomb would be confiscated. I don’t think pre-emptive actions are necessarily contrary to anarcho-capitalism, provided the evidence is clear cut and the intention isn’t in too much doubt. But let’s say he was a nutjob. His guardians have a duty – perhaps not legal, but certainly moral – to prevent him from blowing up the neighborhood. It’s in their interests, too. To not stop him is to become accomplices to his crime, were it to happen. But what if he’s perfectly sane, and has made no threat and his behavior and character exclude mass murder? Certainly tell him to be careful.
I don’t know. We must be careful that in our fear we don’t act like the state – unwarranted pre-emptive violence, illegal confiscation, coercion and the like. As heartless as it sounds, if he is no threat and there is no reason or just cause to take his bomb, then we should not; but if he uses it, his life may be forfeit. I don’t want to go down a road of witch hunts, “he could be dangerous” fear mongering and the like. Ultimately, I’d treat a bomb just like a rifle. My owning an AK and M44 does not mean that I will go out and murder someone, it only means that it is within my power. Bomb or gun doesn’t matter. A man well motivated can kill a sickening number with a pair of pistols or a shotgun or an M14, just as a well motivated man can do the same with a bomb. Does it actually matter how many die, and by what method?
“Any man’s death diminishes me.”