[ChrisRR]

neither one works flawlessly in isolation. You can explain to a child why you don't want them doing something until you're blue in the face. But in all likelihood they're going to want to do it more. The backup is then to block the app on their phone

Sure, they can still use their friends' phones, but you can only protect a child so much. You've made a good start by explaining the issue and banning the app, but you can't track them all day to make sure they're not doing it elsewhere.

[alisonkisk]

Instead of focusing their attention by telling them how bad it is, give them something else to do and introduce you them to other children raised with similar values

[ChrisRR]

You can do that all you like, you can give them all the hobbies they could ever need to be busy. But eventually one of their friends is going to share the app with them when they're playing together