As an event organizer, you have the ability to display what your license holders can or cannot see when they scan a lead. Under the "Registration Form", there is a column titled "Lead Retrieval" where you can mark each field as "hidden" or "visible". This is also the case for custom questions. If a field is “visible”, lead retrieval users can view this field whether or not the lead contains a response within that specific field.
See the screenshot below: