You can prevent hotlinking of your JS and CSS files using your server config (for instance, in .htaccess on Apache). That will make it harder but it won't stop

You can prevent hotlinking of your JS and CSS files using your server config (for instance, in .htaccess on Apache). That will make it harder but it won't stop them copying the files locally. Lots of tutorials to prevent this are a quick Google away. You could even serve up an alternate CSS file for offenders that warns them from hotlinking your resources by prepending something to the body tag that is styled like a massive warning box and hiding everything else.