Talk is Cheap

Hopefully actual judges in actual courts already know this, but parents, teachers, newly appointed bosses and other decision makers may not:

A. Con artists and manipultors say whatever works to get them what they want and pretending naivity, first offense or first time for anything and "I had no idea, honest and for true" works shockingly often to buy them substantial latitude they often don't really deserve in most social settings.

B. Even if it's true, it's irrelevant. Ignorance of the law is no defense and "I've been successfully fast talking my way out of consequences from age five, so you can't actually punish me. No one ever does." sure as hell should not be a defense.

At a bare minimum, check their story. My lying little brat lived in terror of me checking his story and eventually quit that garbage.

I was the mominator and absolutely never, ever would stop until your lie is exposed. I was Darth Mom.

One of the scariest parts of his childhood was me checking his story. Turns out randomly making up BS at age seven isn't so clever after all. 

Most nonsense a kid that age makes up isn't very plausible. If you are an adult, you probably know it's BS on the face of it.

Do the future a favor and let the kid know you know. Don't convince them they are BRILLIANT at lying when they aren't.