When they are even referencing/loading resources from your server, you could serve some "Thx for copying my design, the invoice is on its way."-images to their

When they are even referencing/loading resources from your server, you could serve some "Thx for copying my design, the invoice is on its way."-images to their pages: http://altlab.com/htaccess_tutorial.html http://altlab.com/htaccess_tutorial.html ;)