Kim this isn't something I'd normally recommend, but do you know anyone who is a policeman?
Maybe they could help her learn. ...about being a good girl and leaving her belt on, rather than no it's naughty (I know it is - but Darcy seems to go better with "this is how you can be a fantistic little helper" as opposed to the attention for being naughty). I wouldn't recommend however getting them to show her what happens to naughty girls etc cos then they beocme frightened of the cops (nothing more heartbreaking I can tell you).