I'm new to Elementary OS. Installed it on my kids old imac (because OSX parental controls are seriously broken), only to find out Elementary has the exact same issue! I added a list of sites to block, but they can still be opened from the managed user accounts. Blocked AppCenter, but it opens up with no issue on their accounts! Any chance this will be fixed? I'd rather not have to change the hosts file and block these sites from all accounts.