The obvious one is to don't use and editor if you don't want the people to edit it. Use a div and show it there and create the editor only when the user is allowed to change the text.
It also has the benefit that the page will load faster and users won't be wondering what's that toolbar about.
Re: Lock Edit Area so Users cannot Change/Alter Text
It also has the benefit that the page will load faster and users won't be wondering what's that toolbar about.