Thanks @tobiaseigen I want to suggest, not enforce that members of a given group watch a Category. In our use cases, it’s fine if they want to change to notify, or just unwatch if they don’t want all the emails.
This is solved for all new users in this bit of awesome by @zogstrip
However, it doesn’t help when there’s a new category, and I want to add it for existing users [without diving into the database]