Could put up a dialog when the user first gets to the Schedule Edits page, or when they click on "Generate PDF". One of these actions would trigger a quick check for notes to the registrar that appear to be old (maybe they date stamp is old, or there are no other edits, and the only thing that would show up on the pdf is the note to the registrar...and the date stamp is old).
But would this dialog be too annoying? Maybe need to bounce this idea off some users first....
In any case, if we were to do this, it would give the user the option to delete the stale notes to the registrar right there in the page, or to mark them for deletion, and then clicking on submit does the actual deletion.