[mrxd]

OK, but what if a parent believes that there's a 75% chance of kidnapping (reality: 0.01%), but they leave their child unattended? Arguably they haven't done anything wrong because their child was not exposed to any risk in reality.

To put it differently, what if I point an unloaded gun at someone an pull the trigger? No harm is done, but if I believed the gun was loaded, the moral calculus would change. The reality that no one was harmed or even in danger is not necessarily decisive. What I believe to be true at that moment is the difference between a prank and attempted murder.

[hga]

The first two rules of gun safety is that there is no such thing as an unloaded gun (a rule of attitude, admittedly), and that you never let the muzzle of a gun cover something you're not willing to destroy. Rule 3 is to not to put your finger on the trigger until you're on the target, which is not violated here, 4 is to be sure of your target and what's behind it, you might not be doing the latter since you're so sure it's unloaded.

From the viewpoint of US law, you have almost certainly committed a serious crime, unless the other party is playing along, and also believes the gun is unloaded (and there has been at least one recent tragic training fatality where the gun indeed turned out to be loaded).