[Plugin: WordPress SEO by Yoast] Remove seo for roles lower then administrator

I had this need when using WordPress SEO in conjunction with Revisionary. Revisionary allows moderation of user-submitted corrections, but unfortunately didn’t allow moderation of the titles and descriptions set in WordPress SEO. This allowed any user with a “Revisor” role to alter the title or description of the page, unmoderated.

I added the following code to my theme’s functions.php to remove the admin bar and meta boxes (that alter WordPress SEO settings for a post/page) for all Revisor users:

function wpu_check_role( $role_to_check ){
	//check to make sure pluggable.php and user.php have been loaded at this point
	if (function_exists( 'is_user_logged_in' ) && function_exists( 'get_current_user_id' ) ) {
			//check that user is logged in
		if ( is_user_logged_in() ) {
			//load user from logged-in user id
			$user_ID = get_current_user_id();
			$user = new WP_User( $user_ID );
			//not sure why there would be more than one role, but let's iterate through it just in case there's a reason
			if ( !empty( $user->roles ) && is_array( $user->roles ) ) {
				foreach ( $user->roles as $role ) {
					//return true if we have a match
					if( $role == $role_to_check ) {
						return true;
					}
				}
			}
		}
	}
	//no match found
	return false;
}

if( wpu_check_role( 'revisor' ) ) {
	//remove the seo forms when editing posts
	remove_all_actions( 'add_meta_boxes' );
	//remove the seo admin bar item (which just gave an access error when clicked)
	remove_all_actions( 'admin_bar_menu' );
}

Hope this helps others in a similar situation.