Laura Lockpicking in general is quite a useful skill. It's useful when you locked yourself out, want to open up a container,(lead an investigation and need to get access to a building cough)
Laura But back to this forum, I care more how parents can prevent it.
They can't.
There is no such thing as an "unlockpickable" lock. You can only make it harder to lockpick the lock.
Spool pins are extremly idiotproof, since you have to have some experience in lockpicking before you can properly detect one and now how much pressure you need in order to lock the pin in place.
But like I said earlier: Even they are not impossible to unlock.
If you truly want to get your child stuck in a chastity belt, the best thing you can do is... don't even build a lock into it you can open up. You would need to make the CB in a way. that it permalocks after first putting it on. Only disadvange would be, that you would have to drill your daughter or whatever out of the CB.
So yeah. Not really a possible thing to do.
Even an electric lock wouldn't work since very RFID chip can be hacked by using simple tools.