If Notes are enabled any user with a Teacher role in any course can make a note against a participant in their course but save it at site level. This will then be visible to any other teacher in any other course within the site.
We would like to remove the option to create site wide notes as we have concerns about privacy/GDPR. We also have concerns that some teachers do not understand the implications of creating such notes (some of them may think of their course as a 'site').
Looking at the settings and permissions it does not seem that Notes has any granularity as to how it is deployed within the personal/course/site contexts. Currently it is a simple on/off switch. We would like to see Admin settings changed to allow specific contexts to be enabled/disabled.