Here's something interesting. While perusing the IRM online for the 2797 letter, I found this page:
---LINK---
and noticed something at least a little interesting:
Processing Balance Due (TDA) and Return Delinquency (TDI) Undelivered
Destroy all notices marked with "Refused" or "Unclaimed."
Hmm... perhaps I should repair the letter and return "refused"? Didn't I read something about this in another thread?
However, this is a letter, not a notice.