Parents would say yes to Facebook because it has a reputation. If Shadybook wants you to side load then you're not doing it because you don't know what it is,

Parents would say yes to Facebook because it has a reputation. If Shadybook wants you to side load then you're not doing it because you don't know what it is, you don't already have an account outside of iOS garden, and likely will never hear about this company to even install it. It only works for Facebook because they are big enough to establish the relationship outside of Apple's walled garden. I'm not sure what security concerns Fortnite might have either. It's a billion dollar game with a solid reputation. They're not going to start ringing up your credit card with fraudulent charges, and if they did then it would make the news and tarnish that reputation. People interact with many companies outside of the iOS ecosystem just fine.