What is the security principle implemented in this scenario?

The least common mechanism principle advocates for minimizing shared resources among users to reduce potential vulnerabilities. It is focused on ensuring that users have access only to the resources necessary for their tasks. This principle does not directly address user acceptance or usability, making it less relevant in scenarios where user compliance and understanding are key.

The zero-trust model is a security framework that assumes no user or system is trusted by default, requiring verification for every access request. While it enhances security by minimizing trust, it does not necessarily address the usability or acceptance of security measures from a user perspective, which is critical for ensuring compliance.

The fail-safe principle focuses on creating systems that default to a safe state in the event of a failure or error. While important in security design, it does not specifically pertain to how users perceive or interact with security measures, making it less relevant to the scenario that prioritizes user acceptance.