children within the community are more unlikely to be exposed to anything sexual as a general rule than maybe other children
I remember there being a lot of talks in the KH about masturbation, homosexuality, porneia, harlots, concubines, fornication and adultery. Maybe this is true overall, however. It's an interesting point, you make, ItsMyLife.
Not all false accusations are made by toddlers, though. Sometimes accusations made years later by teens or adults are fabricated for various reasons, such as financial gain. I imagine they are tough cases to deal with since physical evidence or witnesses are unlikely to exist, but it's understandable why victims might surpress what happened for so long.