Clubs behaviour in activity streams

[jair101]

I guess I can test it, but I figured others can also benefit from the discussion. Can someone clarify how exactly the different types of clubs behave in activity streams? My assumptions are as follows, feel free to correct me:

Public and Open
- New content (posts, topics, images, events, etc) is visible for all in activity streams, both members and non members. 

Closed and Private
- New content (posts, topics, images, events, etc) is visible in activity streams only for members of the club. 

One other question, is Clubs content shown by default in existing streams or it needs to be added explicitly? I am afraid that those users that have their unread content stream customized might not be aware of the existence of open clubs at all!