If you would like your clients to receive their email confirmations/reminders but they do not want to get an Email Campaign or Review Request, you can disable these directly within a client's record! To do so:
1. Navigate to your Business tab
2. Go to the Clients section
3. Select the client
4. Click Message Settings
5. Deselect the box for Email Campaign and/or Review Requests depending on which emails you would like for them not to receive
Note: if they do not want to receive text reminders either, you can uncheck the "Text messages" box as well
Also, you can tag these clients to keep track of them!