As was raised in http://moodle.org/mod/forum/discuss.php?d=90682, the notes feature of Moodle 1.9 seems to deliberately exclude students from seeing information written about themselves, which is quite different from how their profile, grades, and teacher feedback is handled. It may also present issues in some jurisdictions (including the US and parts of Europe with educational privacy/records laws) that usually suggest that educational records are not the exclusive property of the school but also that of the student (and the parent in case of minors).
IMO, the capability of removing such functionality by adjusting the default roles is not sufficient.
I will post a patch which gives students the default ability to see course and site notes where they are the subject while retaining the ability to have instructors post notes visible only to themselves(except admins). Students can also post notes to themselves if they have edit profile permissions as part of this patch; others could only see them if the use their loginas capability.
This would seem to address the feature that is being requested while avoiding the educational records issue imposed by the current implementation.