Notifications: Subscribe to Ball In Court Changes

Micron team loves notification emails. Looking to add another toggle under "notifications" located in the upper right under each tool to that says "Ball in Court Change". This would send an email to the person who subscribed every time a user is assigned (ball moves courts). From what I can tell, that competes the list of subscriptions since it fills the gap between Form Created and Form Closed.

Below is a cheesy mock up to help illustrate.