I just discovered that I have the opposite problem.
My landscaper installed my system and activated it. This caused the system to be registered in his name -- actually, the name of his teenage son, who performed the setup on his smartphone! He then shared complete access with me, so I am able to operate the system. But the notifications are going to my landscaper's son, rather than to me.
So, +1 to this feature request. I suggest that the most logical thing would be for each authorized user be able to control his own notifications (app and email) independently of any other users. Each authorized user can already change the notification settings in the app, so it is surprising and non-intuitive that the settings don't apply to that user but only to the registered owner.
In the meantime, I'll need to look into re-registering the system in my name -- not sure how to do that!