The workflow is a work in progress as things are ironed out at different places. For the beginning parts of Stream to get various tools into place, it was a 'volunteer' process where if your group was interested in it, then they could sign up for it. If the team was not, then they would not be bothered by it while things were being worked on. This way teams could continue to work in the channels they were used to without getting notifications they would yell and scream about on some internal list about broken processes.
Currently there will be a move of various items to gitlab, but that will also be in stages which will have different deliverables. In one of those future phases, I believe that the notifications will be tied more into the RHEL work teams and notifications will be sent there. This is again to make sure that there are not a lot of broken communication (there will be some, because problems are inevitable) as all the hundreds of spinning plates needed to make this work are brought up to speed.