template engine?

Hi all,

I'm slowly going through the codeigniter manual. In the tutorial it states:

CodeIgniter does not require you to use this class since using pure PHP in your view pages lets them run a little faster. However, some developers prefer to use a template engine if they work with designers who they feel would find some confusion working with PHP.

However, my understanding was that by substituting PHP variables as plain text and removing any other PHP scripts before being rendered by the browser was a much more secure way of handling views.

My question is: does the templating engine with codeigniter prevent PHP scripts within views? And/Or, does codeigniter sanitize PHP echoes when they are called directly from the view?