Adding a "processed" flag to a Drupal Webform, that admins can use to indicate whether or not they've dealt with a particular submission? We're using a Drupal Webform to accept customer requests for a free "kit" that we will mail them.

This works fine on the submission side, but we'd like a simple way to look at the submissions and tell which ones have been fulfilled, and which have not.

So far, I haven't been able to come up with a field that is visible and editable by administrators viewing the results, but not also shown to the customer when they are filling it out.

I realize I could put a checkbox on the form for "fulfilled", and then hide it from the customer with CSS... but I'm hoping there's a better way. Is there?
We have a similar thing where two fields are marked as Private and these are only seen by admins. 





We also only allow authenticated users to submit these type of forms.