[OldTimeCoffee]

Different person, but I have a kid. If your parental technique is 'surveillance', they're just going to go over to friend's house instead. It's like a micro-managing manager, it's going to be really ineffective and compliance is an illusion.

Setting the boundary of 'you can use Discord and only this channel I've setup for you and your friends' works if you've spent their whole life setting reasonable boundaries that you discuss with them. Just like an adult, reasonable boundaries are more likely to be complied with.

To the specifics, they could create a new account/server, but it's really obvious on the server list (set a unique server icon). Discord doesn't have parental controls (e.g., you can't set a settings PIN so the settings can't be changed), but there are a lot of server controls you can setup to restrict access (like really short invite times, for example).