Those rules make sense to me.
There's some complications sometimes though, because when you look at the main Docan/Jenny Wu/Amy Zheng thread, you'll find posts like
https://diysolarforum.com/threads/our-new-go-to-lifepo4-vendor-09-20-21.28696/post-404170
Which are definitely advertisements, but they're more or less in response to people asking directly in the thread for more information from the seller. When that thread got started, I don't think most of us were aware that the sellers that we were reviewing and sharing experiences about were members here on the forum (you can see that they joined the forum weeks before that thread began)
I've had nothing but positive things to say about my experience with that vendor, but I don't think they really get the concept that answering questions from members and trying to post helpful info about their services to interested parties isn't too far away from just plain marketing when it goes out of their own thread and into others.
It seems like corporate corner would probably have been a better place for that thread, but it started as a review thread before turning into a marketing thread through a more or less natural progression