Now I understand you, I think!
You are referring to the Restrictions settings on each device (not via MDM) and setting the Location Services in there to "don't allow changes", so that end-users can't change the per-app settings for Location Services, right?
The "Find My Friends" MDM restriction only greys out the overall Location Services switch, but the end user can still go in and change the per-app settings.
In iOS 11 did that restriction default to "don't allow", then?