For the first question.
The default is turned on to follow the thread.
They have to manually deselect it when they first post if they use the full editor. if they go back to edit, the option does not appear.
This is hard coded and not a config option.(it could be changed to default to no by editing the script)
The member has the option on their follow list menu from the top right to edit those already followed and either delete ,notify or not notify.
Or in their preferences to not be notified at all even future watched items.
On the second question
I never have tested that scenario but I believe it will still be in their follow list and if they are set for notifications they will get the email.
However I do not believe that they can access it if it moved to a private forum.
