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.