Does cutting ties with Persona actually take them out of the picture? Whomever they move to can then relay or sell data to Persona. Third party turtles all the way down. inb4 but they pinky promised...

The appropriate solution would be to send an RTA header [1] from the servers and the client must check to see if parental controls are enabled on the device or in the application. Not perfect, but likely sufficient to protect small children assuming the account is a child account and the parent enabled parental controls. Teens will always be able to bypass controls whether local or third party. Teens can share porn, warez, movies and more in rated-G video games with one another and small children. Or over SFTP/FTP/P2P/S3/HTTPS. Or a million other ways. Have fun playing whack-a-mole.

[1] - https://news.ycombinator.com/item?id=46152074