To be frank, I don’t know any case when Valve forced these rules, and even when someone reported such cases to Steam support directly. The response was just - “Thank you. We will check it out.”, and that’s it.

Self-published developers I am aware of have been considering these “rules” as fair suggestion from Valve who point out that it’s important to Valve stay afloat in competition, where many developers will just follow these getting the point, which is straightforward.

A few developers I know do find following this “rule” a respect towards the platform in general even.