When using the API to add a member I can't figure out how to not have the member watch the card. I tried "subscribed":"false" in the JSON or similarly using the URL address. The members are added by all have the watched box checked.
When I get a card with "all" the fields there is no difference in the JSON if a member is watching or not, and getting all the cards the member is attached to didn't show any differences.
The user updating the card is a board admin.
The API docs have no references to "Watch".