Once the Email Notifications add-on has been enabled, you gain access to the mycred_email_subscriptions shortcode. This shortcode can be used to allow users to select which email notifications they want to receive and which ones they would like to “Unsubscribe” from.
If you have selected to send an email notification to both the user and admin, and the user has selected to unsubscribe from emails, only the admin will receive the email. If emails are set to be sent to the user only, and they unsubscribe, the email will never be sent.
Depending on where in the world you are operating from you might be required to offer a feature like this when sending emails. You should include into your emails information on how your users can unsubscribe from further emails.