Maybe I am just not finding this in the documentation... 
1. Is a "member" automatically a "watcher", with an ability to receive notification(s) of any changes to a work package? 
2. What about a work package "assignee"... do they automatically receive notification(s) of any changes to a work package? 
3. What specifically does doing a "Bulk Edit" and setting the "Email Updates" do? 
4. If "NO" to (1) and (2), is there a way to change that, other than doing a "bulk edit"? 
5. Is there a way to "bulk edit" work packages to make them a "watcher"?