Under Messaging & Notification--It isn't an unsubscribe, but a checkbox that says:
From time to time, the administrators may want to send you email notices.
If you do not want to receive these notices, disable this option.
Receive Email from Administrators
There are some cases in which important email will still be emailed to everyone no matter what this setting is--depends on what the administrator chooses, but I believe this is what you are looking for.