Dear Ramon and Colin,
If you are using an "(add-to-list 'auto-mode-alist ...)" for the gpg
files, that sets the major mode on. If you want to leave the major mode
as Org, do not use auto-mode-alist, but instead use a hook:
(add-hook 'org-mode-hook 'your-function), where your-function should be
one that checks if the file name ends with gpg and if so turns your
sensitivity-mode on.
Alternatively, define another major mode:
#+BEGIN_SRC emacs-lisp
(define-derived-mode org-but-sensitive-mode org-mode
...)
#+END_SRC
and copy in "..." whatever your sensitive-minor-mode has.
Best,
Jorge.
