I see. May "auto" could then be "Default (on)" or "Default (off)", as per MC's internal configuration for the field.
I considered the Deep Search idea, but was almost certain it would be rejected. :-) So I'm glad you thought of it!
And off topic, btw, I'm LOVING the ability to tag mass fields via MCWS, and the clipboard being in RFC 4180 format! Being able to send an MCC command to copy the clipboard means I don't have to force users to Export to MPL, or manual copy.