country flag icons in the UI

hi,

I have seen that some applications use icons of flags to indicate
countries (e.g. the deluge torrent client uses that to indicate the
origin or a peer). I was wondering if that is something that would be
encouraged or discencougaraged. If encouraged those flags could become
part of the icon theme (so that we would not need separate packages such
as famfamfam-flag-png under ubuntu).

Some guidelines regarding pitfalls when to use them and when not might
be helpful too. I am writing a small toy to analyse media content I was
considering to use flag icons to indicate the content languages (per
stream/subtitle).

Stefan