CAN SPAM and system failure (data loss)

We have always been compliant with CAN SPAM regulations (telling people who we are, providing unsubscribe links etc).

Recently we had a system failure and some unsubscribe requests may have been lost before we could see them. The end users would have assumed they had unsubscribed.

The pages on the FTC website don’t seem to address this situation.

I am not looking for legal advice, you are not my lawyer blah, blah, blah.

We could simply send everyone a non-commercial mail, but has anyone else run into this or have a cite as to what people have done in this situation?

We’ve managed to solve this… the server logs contain all the data we need. I’d still be interested in how system failure is addressed.