Thats just one of those bullshit things that will have to be a matter of willpower. They are legally allowed tk target children with their products. I have the downloads restricted on their tablets and just never approve Roblox when they ask for it. They did uninstall runescape when I gave them that tho :(

Edit: and these examples I give are just to show how easy it is to monitor without monitoring. I set this stuff up once.