How to protect custom content in Membership

How can I protect custom content that is displayed without the use of a shortcode? Does the Membership plugin have a couple of simple API methods that can make it easy to use the content protection system in code? I found the method 'current_user_on_level()' in another post, but not sure if that is stock WP or what. It would be nice if it would take into account the admin role, just like the shortcode function.

Also, is there a method call to print the content protection message that is entered in the admin via code?