Site Owners Can Remove Retention Labels

With a site owner I can remove/clear a retention label, but a member account can not.  When a member attempts to remove a label I see the message "Error: The label that's applied to this item prevents it from being edited or deleted. Check the item's label for more details."  One would think this would be the same behavior for an owner but that does not appear to be the case.

Has anyone else observed this behavior? 
Does anyone know how to prevent site owners from removing retention labels?