This can't be an uncommon problem for any help desk implementing Service Cloud... but the best practice/solution eludes us.
Once mail to case is setup, there is nothing out of the box preventing a customer from emailing us back after a Case is closed. Their response is essentially lost/buried in the case without anyone knowing.
From what I've gathered thus far, it seems a custom trigger must be created to detect such a reply.
Anyone else faced this issue?