[toomuchtodo]

I suppose the best you can do is indicate how to re-subscribe in the unsubscribe confirmation email and say, “you should save this email! Here are alternate channels to receive your schedule if needed.”

Perhaps you could notify the manager when a user unsubscribes? Puts the ball in their court to notify the user (their employee) they aren’t going to get critical emails. Make sure any unsubscribes show up in a log available to your customer.