When a user is invited to join an organisation, an email is send to the user with a hyperlink were the user can accept the invitation. After the invitation is accepted, the owners of an organisation must confirm the user to admit the user to the organisation.
An email should be send to the owners so they are aware that the user accepted the invitation. An email should be send to the user after the owner confirmed the user. This way some out-of-band chatter can be prevented because the involved parties receive notifications to progress enrolling the user.