Applied in changeset 6d504699630955f9d2b5ebe0a4a8c68849714879.
Discussion: http://kune.cc/#!kune.docs.12.4085
I suggest to introduce a new rigth system as google (or picassa, doodle...) do: authorize people who have a link to access to this information.
With a special link (generated id as google doc), it should be difficult (but not impossible) to someone to have this access.
If it is done, this should be mentionned (in tooltip for example).
For example, this could useful to display kune calendar into google calendar.