Encoding for a file containing filenames?

[Juanma Barranquero]

A few days ago I installed in the trunk a patch for ido.el which
forces the ido history file (an elisp file containing several lists of
filenames and directories) to be saved in a given coding system and
that coding system recorded as a local variable.

At that moment I used

  (or file-name-coding-system
      default-file-name-coding-system)

because it seems logical to save filenames in the current filename
coding system.

However, I'm having second thoughts. Wouldn't be safer to use an
encoding that can save anything, like emacs-mule? Should it depend on
the setting of default-enable-multibyte-characters?

             Juanma