In my form I have several Admin Only fields. They don't show up on the form in the front end but they do appear on the confirmation page and in the confirmation email to the user. I am using {all_fields} for both the confirmation page and the confirmation email. I use {all_fields} because I like your pre-formatted layout which saves me time. But it is very important that users do not see "Admin Only" fields.
The Admin Only fields are "Choose Category" and a section break called "Admin Only". See the form at:
http://www.haring.com/kh_foundation/grants/grant-application
Thank you for your time.