If you need to stop bad bots from scrapping your site, the best way to achieve this is to use .htaccess directives. Everyone, whether human or robot, must go through the .htaccess file. Some users use the robots.txt file to do this, but some bots just ignore it, even Google has been known to ignore the robots.txt file.
Using the following rewrite conditions at the end of your .htaccess will stop them in their tracks.
