Hi, I don’t know the background behind this topic but CC-ing don’t actually subscribe them to PR. Either way, notified person just receives single email.
I also subscribe to the patches once I get a CC, I think this is ok.
I don’t think we gain much by abusing the amount of reviewers. It will lead to unclarity of whether the patch is waiting for someone. We already suffer a bit from this because there is no concept of “blocking” reviewers. This would just make the situation a bit worse.