need clarification on coding standards

[Jakeman]

I have been working on my new site for several months now. I have been making extensive use of $_POST and $_REQUEST in some of my custom scripts.

I just came across the "code standards" section of the vB3 documentation - http://www.vbulletin.com/docs/html/codestandards_gpc

$_GET and $_POST variables should be run through the globalize() function in order to ensure that they have evil magic quotes removed from them before being used, with the exception of $_REQUEST['do'] and $_POST['do'], which is used as the controlling variable for deciding which branch of a script is executed. Do not use $_GET / $_POST / $_REQUEST etc. variables in templates.

1) What are magic quotes and why are they evil?

2) I have been using $_POST and $_REQUEST in the templates. Is this horribly wrong or is it just a harmless thing like some of the other coding standards?