On the Security Tab of the General settings of SEO you’ll find only one setting and it’s very important one but by the fault it’s disabled.
What it does is it allows all users instead of just the administrator to use the advance section of the Seo meta box.
The advance section of the SEO box is this section which allows the user to change a post to be either index or no index and to set the the Url.
If you don’t trust your users they might set this economical url to their own website which is why this is disabled by default by default if you do trust all your users or atleast all the users than can post to your site.
You can enable this safe settings and they will have access to all of this powerful stuff.