Knowledge of the rules falls on the player, just like in real life. Paying customers reported that the advertising was in the wrong channel. Those customers, and there had to have been several, also pay to have the rules enforced.
A GM DOES review the reports. No actual penalty is applied to the account until a GM has approved it based on the chat logs attached to the reports.
It is not the automated system you seem to think it is. The only think “mass reporting” can do is squelch an account pending GM review. It was put in well over a decade ago for gold spammers and their ilk.
This policy on advertising was put in place in 2022. It is pinned to the top of General Discussion and is in the Support Knowledge base as well.