Hide 'who has list opened'

I just noticed that inside a SharePoint list you now see which other users hav

e opened it. However, you also see this when you are a user with 'read' permissions and no permissions to browser user details. In terms of privacy this is absolutely not what we want.

We have multiple clients working in the same list (they can't see each other's records) but we really do not want them to see each other. 

How can I hide this information as soon as possible?