Suppress email notifications for a specific user and / or notification type

Summary

We have a requirement that at least one user does not wish to have email notifications to confirm receipts - they are happy to accept the notification in the worklist - how can I achieve this?

Content

We have at least one user who would like to not get emails asking them to confirm receipts, they are OK with them coming into the worklist though.

Are either of the following possible - 

1. Suppress all emails for a single user, but allow worklist notifications

or

2.Use the messaging filter to send confirm receipt notifications to only the worklist. I have looked at the messaging filter as this seems the most likely solution but I am struggling to link the attributes that I can select on in the filter, and the attributes that I can see on the worklist.