Duck programming is manageable. It starts with recognizing that while it may be designed to be carried out by people who are not professional coders, it is still programming, and must be managed with the same processes you use to manage code:
- Document requirements for the duck programming using the same system the team uses for programming in code.
- Stage changes through testing and/or staging environments, then deploy the validated changes to production.
- Build a system that allows users and analysts to write and run automated tests for the duck programmed functionality.
- Do not allow live changes to duck programmed systems.
- Build reversions and change management into the duck programming system.
Very relevant to Drupal, with its large proportion of UI-based development. And Drupal's making it more possible to do all of that listed above.