How to prevent or handle automated out-of-office replies in bugs, etc.

In relation to question 47125, we sometimes have projects subscribers activating auto-responders on their mail account, such as out-of-office replies. Some auto-responders properly ignore mailing-list messages (based on the mail headers), but most of them have trouble recognizing bug/merge proposal notifications as mails that should be ignored.

This can lead to a great amount of unwanted spam-like comments on our project resources.

As an example, we currently have this problem on OpenERP projects (openobject-addons, openobject-server, etc.) with this subscriber: https://launchpad.net/~ovailly He is adding automatic comments on each new bug or new merge proposal.

How can we, as project leaders, cope with such situations? (other than of course asking people to avoid setting up auto-responders)
Can we remove the unwanted comments somehow?
Can we temporarily disable the user's subscriptions ourselves (as a way to prevent further spam), or do we need to ask an admin (here or on IRC) to do it for us?

Thanks!