Originally posted by: Wings-of-Fire
You could, if you had an inventory of every domain user. Besides, if they create an account just to receive mails from domain account, it doesn't matter if he/she uses it regularly or not. They can use their accounts to watch whenever they want to!
If it's not feasible then I'm afraid, there's no solution for this problem. Like I said, it's a Gmail account and Gmail doesn't give personalization privileges. You can request the users not to delete the files but you can't stop if anyone deliberately deletes them.