HMVC Routes: Protected methods result in warning instead of 404

I've been using HMVC modular extensions. I have a base class in which I've defined some protected methods available to all inheriting controller, however I don't want them to be accessible using URL. When trying to access with URL, I get a warning instead of 404 error. It would be great if these could return 404 as I believe only public methods are intended to be available as routes.

Code:

Severity: Warning

Message: call_user_func_array() expects parameter 1 to be a valid callback, cannot access protected method Controller::method()

Filename: core/CodeIgniter.php

Line Number: 532