System notes for adding/removing scoped labels
See design ideas in #9175 (comment 153360179).
With scoped labels (#9175 (closed)), when you add a scoped label, another label might be automatically be removed. That may not be immediately clear to users and be confusing why one action caused another action automatically.
System notes should help with clarifying this. Either we can combine system notes or update the individual system notes to clarify.