What happens if my child disables the Child app on their phone?

If your Child is tech-savvy then yes this is possible but, should this happen, the Virtual Private Network (VPN) will be disabled and you as the Parent will receive a Connection Failure Alert notification indicating that there is a loss of connection with a Child’s device, and that the device in question is no longer protected. This will afford you as the Parent the opportunity to take appropriate action to rectify the situation.