After reading the Apple Newsroom article The facts about parental control apps I get the feeling certain options for the SM App controlling non-supervised devices might come to an end....
This paragraph is the most telling ..."Over the last year, we became aware that several of these parental control apps were using a highly invasive technology called Mobile Device Management, or MDM. MDM gives a third party control and access over a device and its most sensitive information including user location, app use, email accounts, camera permissions, and browsing history."