shadow-inhibit-overload

shadow-inhibit-overload is a variable defined in `shadowfile.el'.
Its value is

nil

Documentation:
If non-nil, shadowfile won't redefine M-x save-buffers-kill-emacs.
Normally it overloads the function `save-buffers-kill-emacs' to check for
files that have been changed and need to be copied to other systems.

You can customize this variable.