By the time you've rendered the page, it's already too late. In rendering the page you're running the untrusted code. Wordpress themes are a double-edged swor

By the time you've rendered the page, it's already too late. In rendering the page you're running the untrusted code. Wordpress themes are a double-edged sword--Wordpress became what it is today because of the flexibility that themes provide, but it comes at a cost. Other theming engines traded flexibility for security, and as a result aren't nearly as popular.