If you want to prevent people from downloading your webplayer and putting it up on their own site, you might want to have a look at Application.absoluteURL in the documentation. It will allow you to detect if your webPlayer is still where it’s supposed to be or not…
This still doesn’t stop anyone from linking to your webplayer directly though, which might be even worse since you’re now also paying for the traffic.
If you want to try and stop other people from linking to your webplayer from within their websites, check out the example given on the bottom of this page…