Their TOS essentially just says "Don't use the app"
> NightOwl app cannot be held responsible in any circumstances for Shared traffic fees or any other costs the User may incur in accordance with agreements with their internet service provider. The Application use might be prohibited or restricted by the User's service provider or applicable laws. The Application may not be compatible with all service providers' policies and regulations. The User should confirm the ability to use the Application with their service provider.
> NightOwl app cannot be held responsible in any circumstances for Shared traffic fees or any other costs the User may incur in accordance with agreements with their internet service provider. The Application use might be prohibited or restricted by the User's service provider or applicable laws. The Application may not be compatible with all service providers' policies and regulations. The User should confirm the ability to use the Application with their service provider.