Puppies
Kids are puppies. They will "steal". Not understanding completely all the rules, they will convert to their own use that which isn't "theirs".
I remember an early on psychological test I was given. "Have you ever stolen anything?" My honest answer was "Yes".
About 30 questions later a question was "Have you ever been punished for stealing?" Another completely honest answer was "No".
Never trust anyone who says they haven't appropriated that which wasn't theirs. Oh, you can trust them, but to what? They just don't recognize it.
Arf