[Mailman-Users] How to track down Digest spam reporter

We have a fairly active mailing list where at least one Hotmail user is marking every Digest message they receive as "spam". We receive the reports from Hotmail, but we have no way of knowing which subscriber is causing these spam reports (or we'd remove them, of course).

Normally we can turn on "Personalization" and add the subscriber's email address to the footer... but this can't be done for Digests. Any other ideas on how we can track down this spam reporter and get them off the list, short of moving every Hotmail user off the digests? And, as a side question, I'm curious about the technical reasons why Personalization can't be available for Digests.

Thanks, in advance!

• Scott