The Class of Service (CoS) control of a feature only extends to controlling access to the GUI/TUI where the user manages the feature. If a user had the feature enabled previously, the CoS does not "switch off" the feature.
The following features are actively enabled by users, and will therefore keep on functioning even if you change the user's CoS definition to not allow the use of the enabled feature any more:
Reach Me
Notify Me
You should disable the above features using the User preferences Web pages prior to disabling the features from the CoS.
Note If you use the CoS to disable the above features prior to disabling from the User Preferences Web pages, the user can no longer change the settings for these features. However, if the feature was previously enabled for use, the user can continue to use the feature. Hence, you should ensure that the users are no longer using the features that are to be deleted from their CoS, prior to implementing this change.
For information about the fields on this page, see Class of Service field descriptions.