Just wanted to say it might be a good idea to place an index.htm file in the Themes directory to prevent users from viewing/leeching. I use:
<script>history.go(-1);</script>
more effective (as it doesn't need JavaScript to be turned on) is <meta http-equiv="refresh" content="0; url=../index.php">in the <head> section of the page. Even better is a refresh using .htaccess means. However: if someone knows his way around in coppermine, he/she can always get template.html and style.css by entering the urls directly.
Everything you do won't keep others from stealing your theme though, only make it harder for complete newbies.