My first response was exactly what momof4 said.... something going on at home. Not necessarily anything traumatic, but kids act out due to all kinds of changes.
Being bored, if indeed she is, is NO reason for this kind of behaviour though. I find it hard to believe that if mom/dad are enforcing the no-tolerance-rules for these actions that it would still be getting worse.
I hate to say it, but I agree that the shadowing may be your best option. And if she is missing out on fun things because of it, make sure you are letting her know exactly why it has to be this way.