If I don't want to subscribe to a sub-list, chances are that I don't want to see it in the super-list either. The need for a sub-list probably points towards a need for a sub-group. I would prefer to see less subscription buttons and more specialized groups.
When we have a list of lists (e.g. http://kune.cc/#!kune.lists ) and we want to
(a) subscribe to several
or
(b) know which ones I'm subscribed to
then I must get inside every list to see its status (shown by button Subscribe/Unsubscribe).
Ideally I would be able to see my status in each list right from the index. Even better if the Subs/Unsub button is there so I can also subscribe to several lists from the index.