I hate information being pushed at me. If I want to be informed of something, I should subscribe to an e-mail list or syndicated feed.
I, too, hate information that is pushed at me — interrupting information.
But, even in the up-and-coming redesign of the mass email systems, it won't be opt-out-able. We could turn the complexity knob on the system and click it up from normal complexity past ridiculous level to ludicrous complexity by developing a layer atop Sympa that after the LDAP dynamic groups synchronizations processes runs a separate thing-a-mum-bobber removing persons who went to a custom web page and "opted-out."
Of course, there is a balance. With opt-out's, people will complain that they never heard registration was rescheduled. They never got the email. Why... oh why didn't they get the email? (Because they opted-out 3 years ago.) With no opt-out's, on the other hand, people will complain that they get too many emails.
I think a better strategy is some kind of feedback loop from the receivers of the emails to the Communications Divisions of the University. Tell them that about the reception of too many newsletters. Try to get them to rethink their strategy about how and when they communicate. Notify them of alternate channels of information flow (XML Feeds) that can be used instead of mass emails for certain types of communication. The types of information flow that is voluntary versus "critical" information that should go through the mass email system.
For example, the ITS homepage has XML feeds. People can voluntarily subscribe to that information. In addition to that (for users still not on the Aggregator bandwagon), you can subscribe to the page via email to get notifications when/if there is any new information. (The ITS homepage is powered by the Blog@Case system which makes all of these wonderful things possible.) On top of that, ITS does send out a monthly (or bimonthly(?)) news letter filled with some of the more critical pieces of information.
I think that it isn't a case of opting-out of the mass email lists moreso it is a case that alternate channels of communication should be more widely leveraged.