[Someone]

Or Bluetooth speakers.

The kids may also discover airplay and blast the audio over WiFi to the local audio system (there’s a MDM setting “Require passcode on first AirPlay pairing” to prevent that. See https://support.apple.com/en-gb/guide/deployment/dep0f7dd3d8...)

[CaptainHardcore]

I had not thought about AirPlay or Chromecast. An isolated guest wifi configured on the router would fix that problem.