We have recently rolled out the ability to capture a UID value through a Lightbox or Companion unit. However, we do not support allowing brands to hide the Lead Capture form for users with a UID. We would need to support some additional JavaScript that would further customize the launch URL for a Companion or Lightbox to allow a brand to set up a Query Parameter split that lets users with a UID pass the Lead Form.
https://www.loom.com/share/24db4314a1cd41c89dccaab75fd78600?sid=7f9d251b-0526-47e4-a25f-c97823898eb9