Add email notification when inbox is full

[Nazenn]

I maintain a mod on behalf of another mod author whos too busy, but he handles all the permissions etc. Recently no one could get in touch with him because his inbox was full but he was unaware.

Is there a way where you can get notified when your inbox is full other then actually having to go and manually check it?
If not, I would appreciate if a system could be added that when the inbox is full an automatic email is sent out to your registered email to notify you.

Thanks :)