Re: [gmane.emacs.bugs] Emacs fails to start properly if the current working directory is on a vfat or ntfs filesystem

[Richard Stallman]

    That's indeed what we should do.  If and when we ever get support for
    filesystem-knowledge in the code, we may revisit this choice, but for
    now, please someone change the code that auto-generates those filenames
    to avoid characters known to be problematic.  Or better yet: to only
    use those chars expected to be always work.

I think that changing from # to something else is a drastic change,
and I would not want to do that now.  For instance, as Miles said,

    Isn't that sort of dangerous?  If Emacs only uses characters which are
    _garanteed_ to work on any no matter how stupid, that would seem to
    dramatically increase the chances of a clash with a real filename...

There could be other characters that in practice will be no pain.
But I think it is wiser to try that in Emacs 23.