Author here. Thanks for the feedback, I really appreciate.

The code in the screenshot was written poorly on purpose, only for the need of this blog post.

Developers make mistakes at any level of seniority. It's less likely to happen when you reach a certain proficiency in writing C# code, but it's still a possibility. Mistakes can also go through some cracks at review time.

So these are definitely automated guardrails that don't require humans with specific knowledge to enforce them.