You can turn a metric on or off for a particular client. This way, they won't see it in their profile and be confused if they should be tracking it.
To do so, go to your Client page and find a particular client.
Hover over their row and you'll see a small graph icon appear on the far right side of their client row.
Click on this icon and you'll be taken to the client's metrics page.
Find the metric you want to turn on/off and click the toggle switch.
Once you refresh the page, all "off" metrics will go to the bottom of the page.
Any metric that is "off" will not show up in the client's data tab on the web or on the app.
You can always turn a metric back "on" for a client and all their previous data will re-appear.